Ironwood Pharmaceuticals (IRWD) 10-K 18 Feb 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Cover [Abstract]
Entity Central Index Key	0001446847
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-34620
Entity Registrant Name	IRONWOOD PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3404176
Entity Address, Address Line One	100 Summer Street
Entity Address, Address Line Two	Suite 2300
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02110
City Area Code	617
Local Phone Number	621-7722
Title of 12(b) Security	Class A Common Stock, $0.001 par value
Entity Listing, Par Value Per Share	$ 0.001
Trading Symbol	IRWD
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
ICFR Auditor Attestation Flag	true
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1,858,612,775
Entity Common Stock, Shares Outstanding		159,221,969
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	Boston, Massachusetts

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 620,129	$ 362,564
Accounts receivable, net	114,042	122,351
Prepaid expenses and other current assets	8,689	9,189
Restricted cash	1,250	1,735
Convertible note hedges	1,115
Total current assets	745,225	495,839
Restricted cash, net of current portion	485	485
Accounts receivable, net of current portion	23,998	23,401
Property and equipment, net	7,575	8,929
Operating lease right-of-use assets	15,350	16,576
Convertible note hedges		13,065
Deferred tax assets	333,294
Other assets	1,000	943
Total assets	1,126,927	559,238
Current liabilities:
Accounts payable	935	661
Accrued research and development costs	15,896	1,898
Accrued expenses and other current liabilities	23,566	26,486
Current portion of operating lease liabilities	3,127	3,128
Current portion of convertible senior notes	116,858
Note hedge warrants	1,316
Total current liabilities	161,698	32,173
Note hedge warrants		12,088
Convertible senior notes, net of current portion	337,333	430,256
Operating lease obligations, net of current portion	18,484	20,318
Other liabilities	3,501	1,763
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value, 75,000,000 shares authorized, no shares issued and outstanding
Class A Common Stock, $0.001 par value, 500,000,000 shares authorized and XXX shares issued and outstanding at December 31, 2021 and 500,000,000 shares authorized and 160,616,675 shares issued and outstanding at December 31, 2020	162	161
Additional paid-in capital	1,543,357	1,528,535
Accumulated deficit	(937,608)	(1,466,056)
Total stockholders' equity	605,911	62,640
Total liabilities and stockholders' equity	$ 1,126,927	$ 559,238

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	75,000,000	75,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	162,036,461	160,616,675
Common stock, shares outstanding	162,036,461	160,616,675

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Total revenues	$ 413,753	$ 389,523	$ 428,413
Cost and expenses:
Cost of revenues		3,136	23,875
Settlement on non-cancellable purchase commitments			(3,530)
Research and development	70,405	88,062	115,044
Selling, general and administrative	111,133	140,003	172,450
Gain on lease modification			(3,169)
Restructuring expenses	(44)	15,382	3,620
Total cost and expenses	181,494	246,583	308,290
Income from operations	232,259	142,940	120,123
Other (expense) income:
Interest expense	(31,150)	(29,478)	(36,602)
Interest and investment income	726	1,504	2,862
Gain (loss) on derivatives	(1,178)	(6,129)	3,023
Loss on extinguishment of debt			(30,977)
Other income		24	514
Other expense, net	(31,602)	(34,079)	(61,180)
Income from continuing operations, before income taxes	200,657	108,861	58,943
Income tax (expense) benefit	327,791	(2,685)
Income from continuing operations	528,448	106,176	58,943
Loss from discontinued operations, net of income taxes			(37,438)
Net income	528,448	106,176	21,505
Comprehensive income	$ 528,448	$ 106,176	$ 21,505
Income per share from continuing operations, net of income taxes - basic (in dollars per share)	$ 3.26	$ 0.67	$ 0.38
Income per share from continuing operations, net of income taxes - diluted (in dollars per share)	3.21	0.66	0.38
Loss per share from discontinued operations, net of income taxes - basic (in dollars per share)			(0.24)
Loss per share from discontinued operations, net of income taxes - diluted (in dollars per share)			(0.24)
Net income per share - basic (in dollars per share)	3.26	0.67	0.14
Net income per share - diluted (in dollars per share)	$ 3.21	$ 0.66	$ 0.14
Weighted average shares used in computing net income per share - basic: (in shares)	162,245	159,427	156,023
Weighted average shares used in computing net income per share - diluted: (in shares)	164,418	160,655	156,023
Collaborative arrangements revenue
Revenues:
Total revenues	$ 412,784	$ 381,545	$ 379,652
Sale of active pharmaceutical ingredient
Revenues:
Total revenues	$ 969	$ 7,978	$ 48,761

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional paid-in capital	Accumulated deficit	Total
Balance at Dec. 31, 2018	$ 154	$ 1,394,603	$ (1,591,128)	$ (196,371)
Balance (in shares) at Dec. 31, 2018	154,414,691
Increase (Decrease) in Stockholders' Equity (Deficit)
Issuance of common stock upon exercise of stock options and employee stock purchase plan, net of cancellations	$ 4	13,597		13,601
Issuance of common stock upon exercise of stock options and employee stock purchase plan, net of cancellations (in shares)	3,121,271
Share-based compensation expense related to share-based awards and employee stock purchase plan		(32,331)		(32,331)
Equity component of convertible senior notes		92,502		92,502
Equity component of issuance costs for convertible senior notes		(2,092)		(2,092)
Purchase of capped calls		(25,159)		(25,159)
Equity component of the partial repurchase of the 2022 Convertible Notes		(26,959)		(26,959)
Dividend of sGC business			(2,609)	(2,609)
Net income			21,505	21,505
Balance at Dec. 31, 2019	$ 158	1,478,823	(1,572,232)	(93,251)
Balance (in shares) at Dec. 31, 2019	157,535,962
Increase (Decrease) in Stockholders' Equity (Deficit)
Issuance of common stock related to share-based awards and employee stock purchase plan	$ 3	18,537		18,540
Issuance of common stock related to share-based awards and employee stock purchase plan (in shares)	3,080,713
Share-based compensation expense related to share-based awards and employee stock purchase plan		31,175		31,175
Net income			106,176	106,176
Balance at Dec. 31, 2020	$ 161	1,528,535	(1,466,056)	$ 62,640
Balance (in shares) at Dec. 31, 2020	160,616,675			160,616,675
Increase (Decrease) in Stockholders' Equity (Deficit)
Issuance of common stock related to share-based awards and employee stock purchase plan	$ 3	19,678		$ 19,681
Issuance of common stock related to share-based awards and employee stock purchase plan (in shares)	3,776,786
Share-based compensation expense related to share-based awards and employee stock purchase plan		22,281		22,281
Repurchases of common stock	$ (2)	(27,137)		$ (27,139)
Repurchases of common stock (in shares)	(2,357,000)			(2,400,000)
Net income			528,448	$ 528,448
Balance at Dec. 31, 2021	$ 162	$ 1,543,357	$ (937,608)	$ 605,911
Balance (in shares) at Dec. 31, 2021	162,036,461			162,036,461

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 528,448	$ 106,176	$ 21,505
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,523	3,564	5,580
Loss on disposal of property and equipment	93	470	146
Share-based compensation expense	22,281	31,175	31,278
Gain on lease modification			(3,169)
Change in fair value of note hedge warrants	(10,772)	(12,172)	16,232
Change in fair value of convertible note hedges	11,950	18,301	(19,255)
Settlement on non-cancellable purchase commitments			(3,530)
Non-cash interest expense	23,935	22,263	19,590
Deferred income taxes (including benefit from valuation allowance release)	(333,294)
Loss on extinguishment of debt			30,977
Changes in assets and liabilities:
Accounts receivable and related party accounts receivable, net	7,712	4,091	(68,893)
Prepaid expenses and other current assets	601	1,515	(1,046)
Inventory, net		648
Operating lease right-of-use assets	1,226	1,167	14,141
Other assets	(57)	(153)	159
Accounts payable, related party accounts payable and accrued expenses	(2,644)	(7,523)	(32,700)
Accrued research and development costs	13,998	(1,058)	(483)
Operating lease liabilities	(1,835)	218	(12,046)
Deferred revenue		(875)	875
Other liabilities	(1,270)	1,029
Net cash provided by (used in) continuing operating activities	261,895	168,836	(639)
Net cash provided by discontinued operating activities			11,364
Net cash provided by operating activities	261,895	168,836	10,725
Cash flows from investing activities:
Purchase of property and equipment	(265)	(1,842)	(7,189)
Proceeds from sale of property and equipment			268
Net cash (used in) continuing investing activities	(265)	(1,842)	(6,921)
Net cash (used in) discontinued investing activities			(4,223)
Net cash (used in) investing activities	(265)	(1,842)	(11,144)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes			400,000
Purchase of capped calls			(25,159)
Proceeds from partial termination of convertible note hedges and note hedge warrants			3,174
Costs associated with issuance of convertible senior notes			(9,048)
Proceeds from exercise of stock options and employee stock purchase plan	19,581	18,546	13,595
Repurchases of common stock	(24,131)
Payments for partial repurchase of 2022 Convertible Notes			(227,338)
Payments on 8.375% Notes due 2026			(156,409)
Net cash provided by financing activities	(4,550)	18,546	(1,185)
Net increase in cash, cash equivalents and restricted cash	257,080	185,540	(1,604)
Cash, cash equivalents and restricted cash, beginning of period	364,784	179,244	180,848
Cash, cash equivalents and restricted cash, end of period	621,864	364,784	179,244
Supplemental cash flow disclosure:
Cash paid for interest	7,216	7,216	17,584
Cash paid for income taxes	3,452	$ 1,848
Non-cash investing and financing activities
Recognition of asset retirement obligation			486
Fixed asset purchases in accounts payable and accrued expenses			$ 1,282
Stock repurchases payable in accrued expenses	$ 3,009

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of cash, cash equivalents, and restricted cash to the condensed consolidated balance sheets
Cash and cash equivalents	$ 620,129	$ 362,564	$ 177,023
Restricted cash	1,735	2,220	2,221
Total cash, cash equivalents, and restricted cash	$ 621,864	$ 364,784	$ 179,244	$ 180,848

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Nature of Business	1. Nature of Business ​ Ironwood Pharmaceuticals, Inc. (“Ironwood” or the “Company”) is a gastrointestinal (“GI”) healthcare company dedicated to advancing the treatment of GI diseases and redefining the standard of care for GI patients. The Company is focused on the development and commercialization of innovative GI product opportunities in areas of significant unmet need, leveraging its demonstrated expertise and capabilities in GI diseases. ​ LINZESS ® (linaclotide), the Company’s commercial product, is the first product approved by the United States Food and Drug Administration (the “U.S. FDA”) in a class of GI medicines called guanylate cyclase type C agonists and is indicated for adult men and women suffering from irritable bowel syndrome with constipation (“IBS-C”) or chronic idiopathic constipation (“CIC”). LINZESS is available to adult men and women suffering from IBS-C or CIC in the United States (the “U.S.”) and Mexico and to adult men and women suffering from IBS-C in Japan and China. Linaclotide is available under the trademarked name CONSTELLA ® ​ The Company has strategic partnerships with leading pharmaceutical companies to support the development and commercialization of linaclotide throughout the world. The Company and its partner, AbbVie Inc. (together with its affiliates, “AbbVie”), began commercializing LINZESS in the U.S. in December 2012. Under the Company’s collaboration for North America with AbbVie, total net sales of LINZESS in the U.S., as recorded by AbbVie, are reduced by commercial costs incurred by each party, and the resulting amount is shared equally between the Company and AbbVie. Additionally, development costs are shared equally between the Company and AbbVie. AbbVie also has an exclusive license from the Company to develop and commercialize linaclotide in all countries other than China (including Hong Kong and Macau), Japan and the countries and territories of North America (the “AbbVie License Territory”). On a country-by-country and product-by-product basis in the AbbVie License Territory, AbbVie pays the Company a royalty as a percentage of net sales of products containing linaclotide as an active ingredient. In addition, AbbVie has exclusive rights to commercialize linaclotide in Canada as CONSTELLA and in Mexico as LINZESS. ​ Astellas Pharma Inc. (“Astellas”), the Company’s partner in Japan, has an exclusive license to develop and commercialize linaclotide in Japan. In March 2017, Astellas began commercializing LINZESS for the treatment of adults with IBS-C in Japan, and in September 2018, Astellas began commercializing LINZESS for the treatment of adults with chronic constipation in Japan. In August 2019, the Company amended and restated its license agreement with Astellas. Effective in 2020, Company is no longer responsible for the supply of linaclotide active pharmaceutical ingredient (“API”) to Astellas (Note 5). ​ In October 2012, the Company and AstraZeneca AB (together with its affiliates) (“AstraZeneca”) entered into a collaboration agreement to co-develop and co-commercialize linaclotide in China (including Hong Kong and Macau) (the “AstraZeneca License Territory”). In September 2019, the Company amended and restated its existing collaboration agreement with AstraZeneca whereby AstraZeneca obtained the exclusive right to develop, manufacture, and commercialize products containing linaclotide in the AstraZeneca License Territory (Note 5). In November 2019, AstraZeneca began commercializing LINZESS for the treatment of adults with IBS-C in China. ​ ​ ​ ​ In November 2021, the Company entered into a collaboration and license option agreement (the “COUR Collaboration Agreement”) with COUR Pharmaceutical Development Company, Inc. (“COUR”), a biotechnology company developing novel immune-modifying nanoparticles to treat autoimmune diseases. The COUR Collaboration Agreement grants the Company an option to acquire an exclusive license to research, develop, manufacture and commercialize, in the U.S., products containing CNP-104, a potential treatment for primary biliary cholangitis, a rare autoimmune disease targeting the liver. ​ These and other agreements are more fully described in Note 5, Collaboration, License, and Other Agreements, ​ The Company is also advancing IW-3300, a guanylate cyclase type C agonist, for the potential treatment of visceral pain conditions, including interstitial cystitis / bladder pain syndrome (IC/BPS) and endometriosis. In December 2021, the U.S. FDA accepted our Investigational New Drug Application, and the Phase I clinical program has commenced in the first quarter of 2022 to evaluate the safety and tolerability of IW-3300 in healthy volunteers. ​ The Company was incorporated in Delaware on January 5, 1998 as Microbia, Inc. On April 7, 2008, the Company changed its name to Ironwood Pharmaceuticals, Inc. To date, the Company has dedicated a majority of its activities to the research, development and commercialization of linaclotide, as well as to the research and development of its other product candidates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Principles of Consolidation The accompanying consolidated financial statements include the accounts of Ironwood and its wholly-owned subsidiaries, as of December 31, 2021, Ironwood Pharmaceuticals Securities Corporation and Ironwood Pharmaceuticals GmbH. Cyclerion Therapeutics, Inc. (“Cyclerion”) was a wholly-owned subsidiary until it became an independent publicly-traded company on April 1, 2019 (Note 3). All intercompany transactions and balances are eliminated in consolidation. ​ Segment Information Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Company’s chief operating decision-maker in deciding how to allocate resources and in assessing performance. The Company currently operates in one reportable business segment—human therapeutics. Reclassifications Certain prior period financial statement items have been reclassified to conform to current period presentation. Discontinued Operations ​ The Company determined that its soluble guanylate cyclase (“sGC”) business, which was disposed on April 1, 2019, met the criteria for classification as a discontinued operation in accordance with Accounting Standards Codification (“ASC”) Subtopic 205-20, Discontinued Operations Cyclerion Separation ​ Use of Estimates The preparation of consolidated financial statements in accordance with U.S. generally accepted accounting principles requires the Company’s management to make estimates and judgments that may affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of revenues and expenses during the reported periods. On an ongoing basis, the Company’s management evaluates its estimates, judgments and methodologies. Significant estimates and assumptions in the consolidated financial statements include those related to revenue recognition; accounts receivable; useful lives of long-lived assets, impairment of long-lived assets, including goodwill; valuation procedures for right-of-use assets and operating lease liabilities; valuation procedures for the issuance and repurchase of convertible notes; balance sheet classification of convertible notes; fair value of derivatives; income taxes, including the valuation allowance for deferred tax assets; research and development expenses; contingencies and share-based compensation. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ materially from these estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known. Cash and Cash Equivalents The Company considers all highly liquid investment instruments with a remaining maturity when purchased of three months or less to be cash equivalents. Investments qualifying as cash equivalents primarily consist of money market funds, U.S. government-sponsored securities, and repurchase agreements. The carrying amount of cash equivalents approximates fair value. The amount of cash equivalents included in cash and cash equivalents was $595.2 million and $349.0 million at December 31, 2021 and 2020, respectively. Restricted Cash The Company is contingently liable under unused letters of credit with a bank, related to the Company’s facility lease and vehicle lease agreements, in the amount of $1.7 million and $2.2 million as of December 31, 2021 and 2020, respectively. The Company records as restricted cash the collateral used to secure these letters of credit. The amount of restricted cash included in current assets and non-current assets was $1.3 million and $0.5 million, respectively, at December 31, 2021. The amount of restricted cash in current assets and non-current assets was $1.7 million and $0.5 million, respectively, at December 31, 2020. Concentrations of Suppliers The Company relies on its collaboration partners and their suppliers to manufacture linaclotide API, linaclotide finished drug product, and finished goods. If any of the Company’s collaboration partners and their suppliers were to limit or terminate production or otherwise fail to meet the quality or delivery requirements needed to satisfy the supply commitments, the process of locating and qualifying alternate sources could require up to several months, during which time production could be delayed. Such delays could have a material adverse effect on the Company’s business, financial position and results of operations. Accounts Receivable and Related Valuation Account The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for credit losses when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices and the overall quality and age of those invoices not specifically reviewed. The Company’s receivables relate primarily to amounts reimbursed under its collaboration, license and co-promotion agreements. The Company believes that credit risks associated with these partners are not significant. The Company reviews the need for an allowance for credit losses for its receivables based on various factors including payment history and historical bad debt experience. The Company had no allowance for credit losses as of December 31, 2021 or 2020. Concentrations of Credit Risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents, restricted cash, and accounts receivable. The Company maintains its cash and cash equivalent balances with high-quality financial institutions and the Company believes that such funds are subject to minimal credit risk. The Company has adopted an investment policy which limits the amounts the Company may invest in certain types of investments, and requires all investments held by the Company to be at least AA- rated, thereby reducing credit risk exposure. Accounts receivable primarily consist of amounts due under the linaclotide collaboration agreement with AbbVie for North America (Note 5). The Company does not obtain collateral for its accounts receivable. The Company previously reflected amounts due from Allergan, net of amounts payable to Allergan, prior to its acquisition by AbbVie as related party accounts receivable, net. Following the acquisition of Allergan by AbbVie, the Company determined that AbbVie is not a related party to the Company (Note 16). The percentages of revenue recognized from significant collaborative partners of the Company in the years ended December 31, 2021, 2020 and 2019 as well as the account receivable balances, net of any payables due, at December 31, 2021 and 2020 are included in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts Receivable ​ Revenue ​ ​ December 31, ​ Year Ended December 31, ​ 2021 2020 2021 2020 2019 Collaborative Partner: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ AbbVie (North America and Europe) 81 % 76 % 98 % 96 % 78 % Astellas (Japan) 1 % 1 % 1 % 1 % 13 % ​ Property and Equipment ​ Property and equipment, including leasehold improvements, are recorded at cost, and are depreciated when placed into service using the straight-line method based on their estimated useful lives as follows: ​ ​ ​ ​ ​ ​ Estimated Useful Life Asset Description (In Years) Laboratory equipment 5 ​ Computer and office equipment 3 ​ Furniture and fixtures 7 ​ Software 3 ​ ​ Included in property and equipment are certain costs of software obtained for internal use. Costs incurred during the preliminary project stage are expensed as incurred, while costs incurred during the application development stage are capitalized and amortized over the estimated useful life of the software. The Company also capitalizes costs related to specific upgrades and enhancements when it is probable the expenditures will result in additional functionality. Maintenance and training costs related to software obtained for internal use are expensed as incurred. Leasehold improvements are amortized over the shorter of the estimated useful life of the asset or the lease term. Costs for capital assets not yet placed into service have been capitalized as construction in process, and will be depreciated in accordance with the above guidelines once placed into service. Maintenance and repair costs are expensed as incurred. ​ Impairment of Long-Lived Assets The Company regularly reviews the carrying amount of its long-lived assets to determine whether indicators of impairment may exist, which warrant adjustments to carrying values or estimated useful lives. If indications of impairment exist, projected future undiscounted cash flows associated with the asset are compared to the carrying amount to determine whether the asset’s value is recoverable. If the carrying value of the asset exceeds such projected undiscounted cash flows, the asset will be written down to its estimated fair value. ​ Income Taxes The Company provides for income taxes under the asset and liability method. Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates in effect when the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance to reflect the uncertainty associated with their ultimate realization. The Company accounts for uncertain tax positions recognized in the consolidated financial statements in accordance with the provisions of ASC Topic 740, Income Taxes ​ Financing Costs Financing costs include costs directly attributable to the Company’s offerings of its equity securities and its debt financings. Costs attributable to equity offerings are charged as a reduction to stockholders’ equity against the proceeds of the offering once the offering is completed. Costs attributable to debt financings are deferred and amortized to interest expense over the term of the debt using the effective interest method. Costs incurred in connection with convertible debt securities are allocated between the liability and equity components. In accordance with ASC 835, Interest ​ Leases Effective January 1, 2019, the Company adopted ASC Topic 842, Leases optional transition method ​ As part of the ASC 842 adoption, the Company elected certain practical expedients, which include: ​ ● Accounting policy election to use the short-term lease exception by asset class; and ● Election of the practical expedient package during transition, which includes: o An entity need not reassess whether any expired or existing contracts are or contain leases. o An entity need not reassess the classification for any expired or existing leases. As a result, all leases that were classified as operating leases in accordance with ASC 840 are classified as operating leases under ASC 842, and all leases that were classified as capital leases in accordance with ASC 840 are classified as finance leases under ASC 842. o An entity need not reassess initial direct costs for any existing leases. ​ Subsequent to the Company’s adoption of ASC 842, the Company elected the post-transition practical expedient, by class of underlying asset, to account for lease components and non-lease components together as a single component for the asset class of operating lease right-of-use real estate assets. ​ The Company’s lease portfolio for the year ended December 31, 2021 included: a lease for its headquarters location, a data center colocation lease, vehicle leases for its salesforce representatives, and leases for computer and office equipment. The Company determines if an arrangement is a lease at the inception of the contract. The asset component of the Company’s operating leases is recorded as operating lease right-of-use assets, and the liability component is recorded as current portion of operating lease liabilities and operating lease liabilities, net of current portion in the Company’s consolidated balance sheets. As of December 31, 2021, the Company did not record any finance leases. ​ Right-of-use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at the lease inception date. Existing leases in the Company’s lease portfolio as of the adoption date were valued as of January 1, 2019. The Company uses an incremental borrowing rate based on the information available at lease inception in determining the present value of lease payments, if an implicit rate of return is not provided with the lease contract. Operating lease right-of-use assets are adjusted for incentives expected to be received. ​ Right-of-use assets and operating lease liabilities are remeasured upon certain modifications to leases using the present value of remaining lease payments and estimated incremental borrowing rate upon lease modification. ​ Lease cost is recognized on a straight-line basis over the lease term, and includes amounts related to short-term leases. The Company recognizes variable lease payments as operating expenses in the period in which the obligation for those payments is incurred. Variable lease payments primarily include common area maintenance, utilities, real estate taxes, insurance, and other operating costs that are passed on from the lessor in proportion to the space leased by the Company. ​ Derivative Assets and Liabilities In June 2015, the Company issued Convertible Senior Notes due 2026 (the “2026 Convertible Notes”, and together with the 2022 Convertible Notes and the 2024 Convertible Notes, the “Convertible Senior Notes”). I Derivatives and Hedging ​ These derivatives are recorded as assets or liabilities at fair value each reporting date and the fair value is determined using the Black-Scholes option-pricing model. The changes in fair value are recorded as a component of other (expense) income in the consolidated statements of income. Significant inputs used to determine the fair value as of December 31, 2021 included the price per share of the Company’s Class A Common Stock, expected terms of the derivative instruments, strike prices of the derivative instruments, risk-free interest rates, and expected volatility of the Company’s Class A Common Stock. Changes to these inputs could materially affect the valuation of the Convertible Note Hedges and Note Hedge Warrants. In August 2019, in connection with the issuance of the 2024 Convertible Notes and the 2026 Convertible Notes, the Company entered into the Capped Calls. The Capped Calls cover the same number of shares of Class A Common Stock that initially underlie the 2024 Convertible Notes and the 2026 Convertible Notes (subject to anti-dilution and certain other adjustments). These instruments meet the conditions outlined in ASC 815 to be classified in stockholders’ equity (deficit) and are not subsequently remeasured as long as the conditions for equity classification continue to be met. ​ Share Repurchases ​ The Company accounts for repurchases of its Class A Common Stock on the trade date by recording the excess of the repurchase price over the par value entirely to additional paid-in capital. All repurchased shares are retired or constructively retired. Issued and outstanding shares are reduced by shares repurchased. ​ Revenue Recognition The Company’s revenues are generated primarily through collaborative arrangements and license agreements related to the research and development and commercialization of linaclotide, as well as co-promotion arrangements in the U.S. The terms of the collaborative research and development, license, co-promotion and other agreements contain multiple performance obligations which may include (i) licenses, (ii) research and development activities, including participation on joint steering committees, (iii) the manufacture of finished drug product, API, or development materials for a partner, which are reimbursed at a contractually determined rate, and (iv) education or co-promotion activities by the Company’s clinical sales specialists. Non-refundable payments to the Company under these agreements may include (i) up-front license fees, (ii) payments for research and development activities, (iii) payments for the manufacture of finished drug product, API, or development materials, (iv) payments based upon the achievement of certain milestones, (v) payments for sales detailing, promotional support services and medical education initiatives, and (vi) royalties on product sales. The Company receives its share of the net profits or bears its share of the net losses from the sale of linaclotide in the U.S. through its collaboration agreement with AbbVie for North America. The Company has adopted a policy to recognize revenue net of tax withholdings, as applicable. Collaboration, License, Co-Promotion and Other Commercial Agreements Upon licensing intellectual property to a customer, the Company determines if the license is distinct from the other performance obligations identified in the arrangement. The Company recognizes revenues from the transaction price, including non-refundable, up-front fees allocated to the license when the license is transferred to the customer if the license has distinct benefit to the customer. For licenses that are combined with other promises, the Company assesses the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. For performance obligations that are satisfied over time, the Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company’s license and collaboration agreements include milestone payments, such as development and other milestones. The Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method at the inception of the agreement. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative standalone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. The Company re-evaluates the probability of achievement of such milestones and any related constraint at each reporting period, and any adjustments are recorded on a cumulative catch-up basis. Agreements that include the supply of API or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. The Company assesses if these options provide a material right to its partner, and if so, they are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded as revenue when the customer obtains control of the goods, which is typically upon shipment for sales of API and finished drug product. For agreements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue when the related sales occur. Net Profit or Net Loss Sharing In accordance with ASC 808 Topic, Collaborative Arrangements Revenue from Contracts with Customers The Company’s collaborative arrangements revenues generated from sales of LINZESS in the U.S. are considered akin to sales-based royalties. In accordance with the sales-based royalty exception, the Company recognizes its share of the pre-tax commercial net profit or net loss generated from the sales of LINZESS in the U.S. in the period the product sales are earned, as reported by AbbVie, and related cost of goods sold and selling, general and administrative expenses as incurred by the Company and AbbVie. These amounts are partially determined based on amounts provided by AbbVie and involve the use of estimates and judgments, such as product sales allowances and accruals related to prompt payment discounts, chargebacks, governmental and contractual rebates, wholesaler fees, product returns, and co-payment assistance costs, which could be adjusted based on actual results in the future. The Company is highly dependent on AbbVie for timely and accurate information regarding net revenues from sales of LINZESS in the U.S. in accordance with both ASC 808 and ASC 606, and the related costs, in order to accurately report its results of operations. If the Company does not receive timely and accurate information or incorrectly estimates activity levels associated with the collaboration at a given point in time, the Company could be required to record adjustments in future periods. In accordance with ASC 606-10-55, Principal Agent Considerations Sale of Active Pharmaceutical Ingredient During the years ended December 31, 2020, and 2019, the Company produced linaclotide API, finished drug product, finished goods, and/or development materials for certain of its partners. As of December 31, 2020, the Company was no longer responsible for the supply of linaclotide API, finished drug product, finished goods or development materials to its partners, though the Company may provide development materials to certain of our partners on a periodic basis. Sales of such development materials have been and are expected to continue to be immaterial. The Company recognizes revenue on linaclotide API, finished drug product, finished goods, and development materials when control has transferred to the partner, which generally occurs upon shipment after the material passed all quality testing required for acceptance by the partner. Prior to the execution of the Amended AstraZeneca Agreement in September 2019, any linaclotide API, finished drug product, and development materials produced for AstraZeneca for China (including Hong Kong and Macau) were recognized in accordance with the cost-sharing provisions of the AstraZeneca collaboration agreement. Other The Company’s deferred revenue balance consists of advance billings and payments received from customers in excess of revenue recognized. Cost of Revenues Cost of revenues includes cost related to the sales of linaclotide API, finished drug product, and finished goods and are generally recognized upon shipment to certain of the Company’s partners outside of the U.S. The Company’s cost of revenues for linaclotide consists of the internal and external costs of producing such API, finished drug product, and finished goods. Research and Development Costs The Company generally expenses research and development costs to operations as incurred. The Company capitalizes nonrefundable advance payments made by the Company for research and development activities and defers expense recognition until the related goods are received or the related services are performed. Research and development expenses are comprised of costs incurred in performing research and development activities, including salary, benefits, share-based compensation, and other employee-related expenses; laboratory supplies and other direct expenses; facilities expenses; overhead expenses; third-party contractual costs relating to nonclinical studies and clinical trial activities and related contract manufacturing expenses, development of manufacturing processes and regulatory registration of third-party manufacturing facilities; licensing fees for the Company’s product candidates; and other outside expenses. The Company has certain collaboration agreements pursuant to which it shares or has shared research and development expenses related to linaclotide. The Company records expenses incurred under such linaclotide collaboration arrangements as research and development expense. Prior to the execution of the Amended AstraZeneca Agreement in September 2019, under the Company’s collaboration agreement with AstraZeneca for China (including Hong Kong and Macau), the Company was reimbursed for certain research and development expenses and it netted these reimbursements against its research and development expenses as incurred. In connection with the execution of the Amended AstraZeneca Agreement, AstraZeneca is fully responsible for all research and development costs incurred related to the development, manufacture, and commercialization of linaclotide in China (including Hong Kong and Macau). Under the Company’s collaboration agreement with AbbVie for North America, the Company is reimbursed for certain research and development expenses and nets these reimbursements against its research and development expenses as incurred. ​ Research and development expense includes up-front payment, non-contingent payment, and milestone payment obligations under the COUR Collaboration Agreement (Note 5). Expense is recognized when the obligation is determined to be probable. ​ Restructuring Expenses Restructuring expenses are comprised primarily of costs associated with exit and disposal activities in accordance with ASC 420, Exit or Disposal Cost Obligations Selling, General and Administrative Expenses The Company expenses selling, general and administrative costs to operations as incurred. Selling, general and administrative expenses consist primarily of compensation, benefits and other employee-related expenses for personnel in the Company’s administrative, finance, legal, information technology, business development, commercial, sales, marketing, communications and human resources functions. Other costs include the legal costs of pursuing patent protection of the Company’s intellectual property, general and administrative related facility costs, insurance costs and professional fees for accounting, tax, consulting, legal and other services. Prior to the execution of the Amended AstraZeneca Agreement, the Company was reimbursed for certain selling, general and administrative expenses and the Company netted these reimbursements against the Company’s selling, general and administrative expenses as incurred. In connection with the Amended AstraZeneca Agreement, effective in September 2019, AstraZeneca is fully responsible for all costs related to the development, manufacture, and commercialization of linaclotide in China (including Hong Kong and Macau). The Company includes AbbVie’s selling, general and administrative cost-sharing payments in the calculation of the net profits and net losses from the sale of LINZESS in the U.S. and presents the net payment to or from AbbVie as collaboration expense or collaborative arrangements revenue, respectively. ​ Share-Based Compensation Expense The Company grants awards under its share-based compensation programs, including stock awards, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) (including both time-based and performance-based RSUs), stock options, and shares issued under the Company’s employee stock purchase plan (“ESPP”). Share-based compensation is recognized as expense in the consolidated statements of income based on the grant date fair value over the requisite service period, net of estimated forfeitures. The Company estimates forfeitures over the requisite service period using historical forfeiture activity and records share-based compensation expense only for those awards that are expected to vest. The Company estimates the fair value of stock options using the Black-Scholes option-pricing model, which requires the use of subjective assumptions including volatility and expected term, among others. The fair value of stock awards, RSAs, and RSUs is based on the market value of the Company’s Class A Common Stock on the date of grant, with the exception of performance-based RSUs with market conditions, which are measured using the Monte Carlo simulation method on the date of grant (Note 13). Discounted stock purchases under the Company’s ESPP are valued on the first date of the offering period using the Black-Scholes option-pricing model to compute the fair value of the lookback provision plus the purchase discount. For awards that vest based on service conditions and market conditions, the Company uses a straight-line method to recognize compensation expense over the respective service period. For awards that contain performance conditions, the Company determines the appropriate amount to expense at each reporting date based on the anticipated achievement of performance targets, which requires judgement, including forecasting the achievement of future specified targets. At the date performance conditions are determined to be probable of achievement, the Company records a cumulative expense catch-up, with remaining expense amortized over the remaining service period. Throughout the performance period, the Company re-assesses the estimated performance and updates the number of performance-based awards that it believes will ultimately vest. Discounted stock purchases under the Company’s ESPP are recognized over the offering period. Compensation expense related to modified awards is measured based on the fair value for the awards as of the modification date. Any incremental compensation expense arising from the excess of the fair value of the awards on the modification date compared to the fair value of the awards immediately before the modification date is recognized at the modification date or ratably over the requisite remaining service period, as appropriate. While the assumptions used to calculate and account for share-based compensation awards represent management’s best estimates, these estimates involve inherent uncertainties and the application of management’s judgment. As a result, if revisions are made to the Company’s underlying assumptions and estimates, the Company’s share-based compensation expense could vary significantly from period to period. Patent Costs The Company incurred and recorded as operating expense legal and other fees related to patents of $1.7 million, $2.3 million, and $7.8 million for the years ended December 31, 2021, 2020 and 2019, respectively. These costs were charged to selling, general and administrative expenses as incurred. Net Income Per Share Basic net income per common share is computed by dividing the net income by the weighted average number of common shares outstanding during the period. Diluted net income per common share is computed by dividing net income by the diluted number of shares outstanding during the period. Except where the result would be antidilutive to net income, diluted net income per common share is computed assuming the conversion of the 2022 Convertible Notes, the 2024 Convertible Notes and the 2026 Convertible Notes, the exercise of outstanding common stock options and the vesting of RSUs and RSAs (using the treasury stock method), as well as their related income tax effects. Subsequent Events The Company considers events or transactions that have occurred after the balance sheet date of December 31, 2021, but prior to the filing of the financial statements with the Securities and Exchange Commission (“SEC”) to provide additional evidence relative to certain estimates or to identify matters that require additional recognition or disclosure. Subsequent events have been evaluated through the filing of the financial statements accompanying this Annual Report on Form 10-K. New Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (the “FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Except as set forth below, the Company did not adopt any new accounting pronouncements during the year ended December 31, 2021 that had a material effect on its consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , March 31 , 2021 ​ In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging— Contracts in Entity’s O

Cyclerion Separation

Cyclerion Separation	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Cyclerion Separation	3. Cyclerion Separation ​ On April 1, 2019, Ironwood completed the separation (the “Separation”) of its sGC business, and certain other assets and liabilities, into Cyclerion. The Separation was effected by means of a distribution of all of the outstanding shares of common stock, with no par value, of Cyclerion through a dividend of Cyclerion’s common stock, to the Ironwood’s stockholders of record as of the close of business on March 19, 2019. Prior to the Separation on April 1, 2019, Cyclerion was a wholly owned subsidiary of the Company. On March 30, 2019, the Company entered into certain agreements with Cyclerion relating to the Separation, including a separation agreement, a tax matters agreement, and an employee matters agreement. ​ Agreements with Cyclerion ​ The separation agreement with Cyclerion sets forth, among other things, the Company’s agreements with Cyclerion regarding the principal actions to be taken in connection with the Separation, including the dividend, which was effective as of April 1, 2019. The separation agreement identifies assets transferred, liabilities assumed by and contracts assigned to each of Cyclerion and Ironwood as part of the Separation, and provides for when and how these transfers, assumptions and assignments occur. The purpose of the separation agreement was to provide Cyclerion and Ironwood with assets to operate their respective businesses and retain or assume liabilities related to those assets. ​ The transfer of assets and liabilities to Cyclerion was effected through a contribution in accordance with the separation agreement as summarized below (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ As of April 1, 2019 ​ Assets: ​ ​ ​ ​ Prepaid expenses and other current assets ​ $ 1,169 ​ Property and equipment, net ​ ​ 10,241 ​ Other assets ​ ​ 21 ​ ​ ​ $ 11,431 ​ Liabilities: ​ ​ ​ ​ Accrued research and development costs ​ $ 5,673 ​ Accrued expenses and other current liabilities ​ ​ 3,149 ​ ​ ​ $ 8,822 ​ Net Assets Transferred to Cyclerion ​ $ 2,609 ​ ​ In addition, the Company received $1.3 million during the year ended December 31, 2019 associated with tenant improvement reimbursement provisions related to the Cyclerion lease in accordance with the separation agreement. ​ The tax matters agreement governs each party’s rights, responsibilities and obligations with respect to taxes, including taxes, if any, incurred as a result of any failure of the Separation to qualify as tax-free. In general, if the parties incur tax liabilities in the event that the Separation is not tax-free, each party is expected to be responsible for any taxes imposed on Ironwood or Cyclerion that arise from the failure of the Separation to qualify as a transaction that is generally tax-free for U.S. federal income tax purposes, under Sections 355 and 368(a)(1)(D) and certain other relevant provisions of the Internal Revenue Code of 1986, as amended, to the extent that the failure to so qualify is attributable to an acquisition of stock or assets of, or certain actions, omissions or failures to act of, such party. If both Ironwood and Cyclerion are responsible for such failure, liability will be shared according to relative fault. U.S. tax otherwise resulting from the failure of the Separation to qualify as a transaction that is tax-free generally will be the responsibility of Ironwood. Each party otherwise agreed to indemnify the other party from and against any liability for taxes allocated to such party under the tax matters agreement and any taxes resulting from breach of any such party’s covenants under the tax matters agreement, the separation agreement, or any ancillary agreement entered into in connection with the Separation. Cyclerion agreed to certain covenants that contain restrictions intended to preserve the tax-free status of the distribution and certain related transactions. ​ The employee matters agreement allocates assets, liabilities and responsibilities relating to the employment, compensation, and employee benefits of Ironwood and Cyclerion employees, and other related matters in connection with the Separation, including the treatment of outstanding Ironwood incentive equity awards. Pursuant to the employee matters agreement, the outstanding Ironwood equity awards held by Cyclerion and Ironwood employees were adjusted in connection with the Separation, with the intent to maintain, immediately following the Separation, the economic value of the awards. No incremental stock-based compensation expense related to the Separation-related adjustments was recognized during the year ended December 31, 2019 (Note 13). ​ Additionally, the Company entered into two transition services agreements and a development agreement with Cyclerion. ​ Pursuant to the transition service agreements, the Company was obligated to provide and was entitled to receive certain transition services related to corporate functions, such as finance, procurement, facilities and development. As of December 31, 2020, both transition service agreements had terminated. Amounts received for services provided to Cyclerion were recorded as other income and amounts paid for services provided by Cyclerion were recorded as selling, general and administrative expense and research and development expense, as applicable. During the years ended December 31, 2020 and 2019, the Company recorded an insignificant amount and $0.3 million, respectively, as other income for services provided to Cyclerion. During each of the years ended December 31, 2020 and 2019, the Company recorded an insignificant amount in both selling, general and administrative expense and research and development expense for services provided by Cyclerion, respectively. ​ Pursuant to the development agreement, Cyclerion was obligated to provide the Company with certain research and development services with respect to certain of Ironwood’s products and product candidates for an initial period of two years, unless earlier terminated or extended. As of December 31, 2021, the development agreement had been terminated. Services received were paid at a mutually agreed upon rate and development activities were governed by a joint steering committee comprised of representatives from both Cyclerion and Ironwood. The Company recorded an insignificant amount, $2.3 million and $4.5 million in research and development expenses under the development agreement during the years ended December 31, 2021, 2020 and 2019, respectively. The Company had an insignificant amount of accounts payable due to Cyclerion as of December 31, 2020. ​ Discontinued Operations ​ Upon the Separation, the Company determined its sGC business qualified for discontinued operations accounting treatment in accordance with ASC 205-20. There were no discontinued operations during the years ended December 31, 2021 and 2020. The following is a summary of expenses of Cyclerion classified as discontinued operations for year ended December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2019 Costs and expenses: ​ ​ ​ ​ Research and development ​ $ 21,792 ​ Selling, general and administrative ​ 15,646 ​ Net loss from discontinued operations ​ $ 37,438 ​ ​ There were no assets or liabilities related to discontinued operations as of either December 31, 2021 or December 31, 2020, as all balances were transferred to Cyclerion upon Separation.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Net Income Per Share	4. Net Income Per Share The following table sets forth the computation of basic and diluted net income per common share (in thousands, except per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 ​ 2020 2019 Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 528,448 ​ $ 106,176 ​ $ 21,505 Denominator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — basic ​ 162,245 ​ 159,427 ​ 156,023 Effect of dilutive securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options ​ ​ 488 ​ ​ 367 ​ ​ — Time-based restricted stock units ​ ​ 1,422 ​ ​ 766 ​ ​ — Performance-based restricted stock units ​ ​ 146 ​ ​ 1 ​ ​ — Restricted stock ​ ​ 117 ​ ​ 94 ​ ​ — Dilutive potential common shares ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — diluted ​ ​ 164,418 ​ 160,655 ​ ​ 156,023 Net income per share — basic ​ ​ 3.26 ​ 0.67 ​ ​ 0.14 Net income per share — diluted ​ $ 3.21 ​ $ 0.66 ​ $ 0.14 ​ The outstanding securities have been excluded from the computation of diluted weighted average shares outstanding, as applicable, as their effect would be anti-dilutive (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Stock options 7,701 11,746 17,194 ​ Restricted stock awards — 2 182 ​ Time-based restricted stock units ​ 102 ​ 209 ​ 3,207 ​ Performance-based restricted stock units ​ 121 ​ 93 ​ — ​ Note Hedge Warrants ​ 8,318 ​ 8,318 ​ 8,318 ​ 2022 Convertible Notes ​ 8,318 ​ 8,318 ​ 8,318 ​ 2024 Convertible Notes ​ 14,934 ​ 14,934 ​ 14,934 ​ 2026 Convertible Notes ​ 14,934 ​ 14,934 ​ 14,934 ​ Total 54,428 58,554 67,087 ​ ​ The potentially dilutive impact of the 2022 Convertible Notes, 2024 Convertible Notes and 2026 Convertible notes (together, the “Convertible Senior Notes”) (Note 10) is determined using the treasury stock method. Under this method, no numerator or denominator adjustments arise from the principal and interest components of the Convertible Senior Notes because the Company has the intent and ability to settle the Convertible Senior Notes’ principal and interest in cash. Instead, the Company is required to increase the diluted net income per share denominator by the variable number of shares that would be issued upon conversion if it settled the conversion spread obligation with shares. For diluted net income per share purposes, the conversion spread obligation is calculated based on whether the average market price of the Company’s Class A Common Stock during the reporting period is in excess of the conversion price of the Convertible Senior Notes. There was no calculated spread added to the denominator for the years ended December 31, 2021, 2020, or 2019.

Collaboration, License, and Oth

Collaboration, License, and Other Agreements	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Collaboration, License, and Other Agreements	5. Collaboration, License, and Other Agreements For the year ended December 31, 2021, the Company had linaclotide collaboration agreements with AbbVie for North America and AstraZeneca for China (including Hong Kong and Macau), as well as linaclotide license agreements with Astellas for Japan and with AbbVie for the AbbVie License Territory. The Company also had an agreement with Alnylam Pharmaceuticals, Inc (“Alnylam”) to perform disease awareness activities for acute hepatic porphyria (“AHP”) and sales detailing activities for GIVLAARI ® ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Collaborative Arrangements Revenue 2021 2020 2019 Linaclotide Collaboration and License Agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ AbbVie (North America) ​ $ 403,085 $ 370,902 $ 327,591 ​ AbbVie (Europe and other) ​ ​ 2,558 ​ ​ 2,196 ​ ​ 1,718 ​ AstraZeneca (China, including Hong Kong and Macau) ​ ​ 743 ​ 682 ​ 32,628 ​ Astellas (Japan) ​ ​ 2,232 ​ 2,128 ​ 10,147 ​ Co-Promotion and Other Agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ AbbVie (VIBERZI) (1) ​ ​ — ​ ​ — ​ ​ 3,723 ​ Alnylam (GIVLAARI) ​ ​ 2,411 ​ ​ 4,302 ​ ​ 2,000 ​ Other ​ ​ 1,755 ​ ​ 1,335 ​ ​ 1,845 ​ Total collaborative arrangements revenue ​ $ 412,784 ​ $ 381,545 ​ $ 379,652 ​ Sale of API ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Linaclotide Agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Astellas (Japan) ​ $ 149 ​ $ 2,017 ​ $ 45,788 ​ AstraZeneca (China, including Hong Kong and Macau) ​ ​ 597 ​ ​ 5,540 ​ ​ 2,973 ​ Other ​ ​ 223 ​ ​ 421 ​ ​ — ​ Total sale of API ​ $ 969 ​ $ 7,978 ​ $ 48,761 ​ (1) The Company had an agreement with AbbVie to perform sales detailing activities for VIBERZI® (eluxadoline) which terminated as of December 31, 2019. ​ Accounts receivable, net, included $138.0 million and $145.8 primarily related to collaborative arrangements revenue and sale of API, collectively, as of December 31, 2021 and 2020, respectively. Accounts receivable, net, included $112.2 million and $110.9 million due from the Company’s partner, AbbVie, net of $5.0 million and $4.3 million of accounts payable at December 31, 2021 and 2020, respectively. ​ The Company routinely assesses the creditworthiness of its license and collaboration partners. The Company has not experienced any material losses related to receivables from its license or collaboration partners during the years ended December 31, 2021, 2020, or 2019. Linaclotide Agreements Collaboration Agreement for North America with AbbVie In September 2007, the Company entered into a collaboration agreement with AbbVie to develop and commercialize linaclotide for the treatment of IBS-C, CIC, and other GI conditions in North America. Under the terms of this collaboration agreement, the Company received a non-refundable, upfront licensing fee and shares equally with AbbVie all development costs as well as net profits or losses from the development and sale of linaclotide in the U.S. The Company receives royalties in the mid-teens percent based on net sales in Canada and Mexico. AbbVie is solely responsible for the further development, regulatory approval and commercialization of linaclotide in those countries and funding any costs. The collaboration agreement for North America also includes contingent milestone payments, as well as a contingent equity investment, based on the achievement of specific development and commercial milestones. As of December 31, 2021, $205.0 million in license fees and all six development milestone payments had been received by the Company, as well as a $25.0 million equity investment in the Company’s capital stock. The Company can also achieve up to $80.0 million in a sales-related milestone if certain conditions are met, which will be recognized when the related sales occur. During the years ended December 31, 2021, 2020 and 2019, the Company incurred $8.2 million, $20.1 million, and $37.6 million in total research and development expenses under the linaclotide collaboration for North America. As a result of the research and development cost-sharing provisions of the linaclotide collaboration for North America, the Company incurred $11.5 million and $5.6 million during the years ended December 31, 2021 and December 31, 2020, respectively, and offset $7.2 million in research and development costs during the year ended December 31, 2019, to reflect the obligations of each party under the collaboration to bear 50% of the development costs incurred. The Company and AbbVie began commercializing LINZESS in the U.S. in December 2012. The Company receives 50% of the net profits and bears 50% of the net losses from the commercial sale of LINZESS in the U.S. Net profits or net losses consist of net sales of LINZESS to third-party customers and sublicense income in the U.S. less the cost of goods sold as well as selling, general and administrative expenses. LINZESS net sales are calculated and recorded by AbbVie and may include gross sales net of discounts, rebates, allowances, sales taxes, freight and insurance charges, and other applicable deductions. The Company evaluated its collaboration arrangement for North America with AbbVie and concluded that all development-period performance obligations had been satisfied as of September 2012. However, the Company has determined that there are three remaining commercial-period performance obligations, which include the sales detailing of LINZESS, participation in the joint commercialization committee, and approved additional trials. The consideration remaining includes cost reimbursements in the U.S., as well as commercial sales-based milestones and net profit and loss sharing payments based on net sales in the U.S. Additionally, the Company receives royalties in the mid-teens percent based on net sales in Canada and Mexico. Royalties, commercial sales-based milestones, and net profit and loss sharing payments will be recorded as collaborative arrangements revenue or expense in the period earned, as these payments relate predominately to the license granted to AbbVie. The Company records royalty revenue in the period earned based on royalty reports from its partner, if available, or based on the projected sales and historical trends. The cost reimbursements received from AbbVie during the commercialization period will be recognized as earned in accordance with the right-to-invoice practical expedient, as the Company’s right to consideration corresponds directly with the value of the services transferred during the commercialization period. Under the Company’s collaboration agreement with AbbVie for North America, LINZESS net sales are calculated and recorded by AbbVie and include gross sales net of discounts, rebates, allowances, sales taxes, freight and insurance charges, and other applicable deductions, as noted above. These amounts include the use of estimates and judgments, which could be adjusted based on actual results in the future. The Company records its share of the net profits or net losses from the sales of LINZESS in the U.S. less commercial expenses on a net basis, and presents the settlement payments to and from AbbVie as collaboration expense or collaborative arrangements revenue, as applicable. This treatment is in accordance with the Company’s revenue recognition policy, given that the Company is not the primary obligor and does not have the inventory risks in the collaboration agreement with AbbVie for North America. The Company relies on AbbVie to provide accurate and complete information related to net sales of LINZESS in accordance with U.S. generally accepted accounting principles in order to calculate its settlement payments to and from AbbVie and record collaboration expense or collaborative arrangements revenue, as applicable. The Company recognized collaborative arrangements revenue from the AbbVie collaboration agreement for North America during the years ended December 31, 2021, 2020, and 2019 as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Collaborative arrangements revenue related to sales of LINZESS in the U.S. ​ $ 400,371 ​ $ 368,603 ​ $ 325,429 ​ Royalty revenue ​ 2,714 ​ 2,299 ​ 2,162 ​ Total collaborative arrangements revenue ​ $ 403,085 ​ $ 370,902 ​ $ 327,591 ​ ​ The collaborative arrangements revenue recognized in the years ended December 31, 2021, 2020, and 2019 primarily represents the Company’s share of the net profits and net losses on the sale of LINZESS in the U.S. The Company incurred $30.3 million, $39.9 million, and $40.5 million in total selling, general and administrative costs related to the sale of LINZESS in the U.S. in accordance with the cost-sharing arrangement with AbbVie, which included $0.3 million, $0.6 million, and $2.4 million in patent prosecution and patent litigation costs, for the years ended December 31, 2021, 2020, and 2019, respectively. ​ In May 2014, CONSTELLA ® License Agreement with AbbVie (All countries other than the countries and territories of North America, China (including Hong Kong and Macau), and Japan) In April 2009, the Company entered into a license agreement with Almirall, S.A. (“Almirall”) to develop and commercialize linaclotide in Europe (including the Commonwealth of Independent States and Turkey) for the treatment of IBS-C, CIC and other GI conditions (the “European License Agreement”). In accordance with the European License Agreement, the Company granted Almirall a right to access its U.S. Phase III clinical trial data for the purposes of supporting European regulatory approval. In October 2015, Almirall transferred its exclusive license to develop and commercialize linaclotide in Europe to AbbVie. Additionally, in October 2015, the Company and AbbVie separately entered into an amendment to the European License Agreement relating to the development and commercialization of linaclotide in Europe. Pursuant to the terms of the amendment, (i) certain sales-based milestones payable to the Company under the European License Agreement were modified to increase the total milestone payments such that, when aggregated with certain commercial launch milestones, they could total up to $42.5 million, (ii) the royalties payable to the Company during the term of the European License Agreement were modified such that the royalties based on sales volume in Europe begin in the mid-single digit percent and escalate to the upper-teens percent by calendar year 2019, and (iii) AbbVie assumed responsibility for the manufacturing of linaclotide API for Europe from the Company, as well as the associated costs. The Company concluded that the 2015 amendment to the European License Agreement was not a modification to the linaclotide collaboration agreement with AbbVie for North America. In January 2017, the Company and AbbVie entered into an amendment to the European License Agreement (the “2017 Amendment”). The 2017 Amendment extended the license to develop and commercialize linaclotide in all countries other than China (including Hong Kong and Macau), Japan, and the countries and territories of North America. On a country-by-country and product-by-product basis in such additional territory, AbbVie is obligated to pay the Company a royalty as a percentage of net sales of products containing linaclotide as an active ingredient in the upper-single digits for five years following the first commercial sale of a linaclotide product in a country, and in the low-double digits thereafter. The royalty rate for products in the expanded territory will decrease, on a country-by-country basis, to the lower-single digits, or cease entirely, following the occurrence of certain events. The 2017 Amendment did not modify any of the milestones or royalty terms related to Europe. In evaluating the terms of the European License Agreement, as amended by the 2017 Amendment (the “Amended European License Agreement”), the Company determined that there are no remaining performance obligations as of September 2012. However, the Company continues to be eligible to receive consideration in the form of commercial launch milestones, sales-based milestones, and royalties. The commercial launch milestones, sales-based milestones and royalties under the Amended European License Agreement relate predominantly to the license granted to AbbVie. The Company records royalties on sales of CONSTELLA in Europe in the period earned based on royalty reports from its partner, if available, or the projected sales and historical trends under the sales-based royalty exception. The commercial launch milestones are recognized as revenue when it is probable that a significant reversal of revenue would not occur and the associated constraint has been lifted. The Company recognized $2.6 million, $2.2 million and $1.7 million of royalty revenue from the Amended European License Agreement during the years ended December 31, 2021, 2020, and 2019, respectively. License Agreement for Japan with Astellas In November 2009, the Company entered into a license agreement with Astellas, as amended, to develop and commercialize linaclotide for the treatment of IBS-C, CIC and other GI conditions in Japan (the “2009 License Agreement with Astellas”). Astellas is responsible for all activities relating to development, regulatory approval and commercialization in Japan as well as funding the associated costs and the Company was required to participate on a joint development committee over linaclotide’s development period. Under the 2009 License Agreement with Astellas, the Company received an upfront licensing fee of $30.0 million and three development milestone payments that totaled $45.0 million and has no remaining performance obligations. In April 2017, the Company and Astellas entered into a commercial API supply agreement (the “Astellas Commercial Supply Agreement”). Pursuant to the Astellas Commercial Supply Agreement, the Company sold linaclotide API supply to Astellas at a contractually defined rate and recognized related revenue as sale of API. Under the 2009 License Agreement with Astellas, the Company received royalties which escalated based on sales volume, beginning in the low-twenties percent, less the transfer price paid for the API included in the product sold and other contractual deductions. ​ During the year ended December 31, 2019, the Company recognized revenue of $27.5 million from the sale of API to Astellas under the 2009 License Agreement with Astellas and the Astellas Commercial Supply Agreement. The royalties on sales of LINZESS in Japan did not exceed the transfer price of API sold and other contractual deductions during each of the periods presented. In August 2019, the Company and Astellas amended and restated the 2009 License Agreement with Astellas (the “Amended Astellas License Agreement”). This amendment to the 2009 License Agreement with Astellas was accounted for as a separate contract. Under the terms of the Amended Astellas License Agreement, the Company is no longer responsible for the supply of linaclotide API to Astellas, and Astellas assumed responsibility for its own supply of linaclotide API in Japan in 2020, other than minimal quantities of API the Company supplied to Astellas in 2020 relating to orders for linaclotide API placed by Astellas in 2019. ​ In connection with the execution of the Amended Astellas License Agreement, Astellas paid the Company a non-refundable, upfront payment of $10.0 million in August 2019. Further, Astellas, in lieu of the royalty payment terms set forth in the 2009 License Agreement with Astellas, is required to pay royalties to the Company at rates beginning in the mid-single digit percent and escalating to low-double-digit percent, based on aggregate annual net sales in Japan of products containing linaclotide API. These royalty payments are subject to reduction following the expiration of certain licensed patents and the occurrence of generic competition in Japan. The Company continued to supply linaclotide API for Japan during 2019 and 2020 at a contractually defined rate. Additionally, Astellas reimbursed the Company for the Company’s performance of adverse event reporting services at a fixed monthly rate until such services were terminated in February 2020. ​ The Company identified the following performance obligations under the Amended Astellas License Agreement: ​ ● delivery of the expanded license of intellectual property, including the applicable manufacturing know-how; ● obligation to supply linaclotide API for 2019; and ● adverse event reporting services. ​ The Company allocated the $10.0 million upfront payment to the delivery of the expanded license of intellectual property and recognized it as collaborative arrangements revenue at contract inception. The Company allocated the $20.4 million in remaining purchase orders for API to the obligation to supply linaclotide API to Astellas for 2019. Consideration for the supply of linaclotide API was recognized over the performance period as linaclotide API is shipped to Astellas. Consideration allocated to the adverse event reporting services was recognized as such services were provided over the performance period based on the amount to which the Company has a right to invoice. ​ Royalties on sales of LINZESS in Japan relate predominantly to the license granted to Astellas. Accordingly, the Company applies the sales-based royalty exception and records royalties on sales of LINZESS in Japan in the period earned based on royalty reports from its partner, if available, or the projected sales and historical trends. ​ During the year ended December 31, 2021, the Company recognized $2.2 million in collaborative arrangements revenue related to royalties and $0.2 million related to the sale of API to Astellas under the Amended Astellas License Agreement. ​ During the year ended December 31, 2020, the Company recognized $2.1 million in collaborative arrangements revenue related to royalties, an insignificant amount of collaborative arrangements revenue related to adverse event reporting services, and $2.0 million from the sale of API to Astellas under the Amended Astellas License Agreement. ​ During the year ended December 31, 2019, the Company recognized $10.0 million in collaborative arrangements revenue related to the upfront fee associated with the execution of the Amended Astellas License Agreement, an insignificant amount of collaborative arrangements revenue related to adverse event reporting services, and $18.3 million from the sale of API to Astellas under the Amended License Agreement. ​ Collaboration Agreement for China (including Hong Kong and Macau) with AstraZeneca In October 2012, the Company entered into a collaboration agreement with AstraZeneca to co-develop and co-commercialize linaclotide in the AstraZeneca License Territory (the “AstraZeneca Collaboration Agreement”). The collaboration provided AstraZeneca with an exclusive nontransferable license to exploit the underlying technology in the AstraZeneca License Territory. The parties shared responsibility for continued development and commercialization of linaclotide under a joint development plan and a joint commercialization plan, respectively, with AstraZeneca having primary responsibility for the local operational execution. In September 2019, the Company and AstraZeneca entered into an amendment and restatement of the AstraZeneca Collaboration Agreement (the “Amended AstraZeneca Agreement”) under which AstraZeneca obtained the exclusive right to develop, manufacture and commercialize products containing linaclotide in the AstraZeneca License Territory (the “AstraZeneca License”). Prior to the execution of the Amended AstraZeneca Agreement, the Company identified the following performance obligations under the AstraZeneca Collaboration Agreement: ● research, development and regulatory services pursuant to the development plan (“R&D Services”); ● Joint Development Committee (“JDC”) services; ● obligation to supply clinical trial material; and ● Joint Commercialization Committee services. ​ Under the original AstraZeneca Collaboration Agreement, the Company shared development costs with AstraZeneca, with AstraZeneca incurring 55% of the net losses from the development and commercialization of linaclotide in the AstraZeneca License Territory. Payments from AstraZeneca with respect to both research and development and selling, general and administrative costs incurred by the Company prior to the commercialization of linaclotide in the AstraZeneca License Territory were recorded as a reduction in expense. Development costs incurred by the Company that pertained to the joint development plan and subsequent amendments to the joint development plan, as approved by the JDC, were recorded as research and development expense as incurred. Payments to AstraZeneca were recorded as incremental research and development expense. During the years ended December 31, 2019, the Company incurred $1.2 million related to pre-launch commercial services and supply chain services. Under the Amended AstraZeneca Agreement, the Company is entitled to receive non-contingent payments totaling $35.0 million in three installments through 2024, of which $10.0 million was received in January 2021. In addition, AstraZeneca may be required to make milestone payments totaling up to $90.0 million contingent on the achievement of certain sales targets and will be required to pay tiered royalties to the Company at rates beginning in the mid-single-digit percent and increasing up to twenty percent based on the aggregate annual net sales of products containing linaclotide in the AstraZeneca License Territory. In connection with the Amended AstraZeneca Agreement, the Company and AstraZeneca entered into a transition services agreement (“AstraZeneca TSA”) and an amended commercial supply agreement (“AstraZeneca CSA”). Under the terms of the AstraZeneca TSA, the Company provided certain regulatory and administrative services through September 2021. Services performed were paid at a mutually agreed upon rate. Amounts for AstraZeneca TSA services were recorded as collaborative arrangements revenue. Under the terms of the AstraZeneca CSA, the Company supplied linaclotide API, finished drug product and finished goods for the Licensed Territory through March 31, 2020 at predetermined rates. The Company evaluated the Amended AstraZeneca Agreement and determined that it would be accounted for as a separate contract because it adds a distinct good or service at an amount that reflects standalone selling price. The following performance obligations under the Amended AstraZeneca Agreement were identified: ​ ● delivery of the expanded AstraZeneca License; ● AstraZeneca TSA services; and ● supply of linaclotide API, finished drug product and finished goods under the AstraZeneca CSA. ​ The Company determined that the non-contingent payments should be allocated to the delivery of the expanded AstraZeneca License. The Company determined that the performance obligation related to the transfer of the AstraZeneca License was satisfied as of the execution date of the Amended AstraZeneca Agreement. As a portion of the payments relating to the transfer of the AstraZeneca License are due significantly after the performance obligation was satisfied, the Company adjusted its transaction price for the significant financing component of $2.6 million. Accordingly, the Company recognized $32.4 million in 2019 relating to the delivery of the AstraZeneca License as collaborative arrangements revenue at contract inception and is recognizing the $2.6 million relating to the significant financing component as interest income through 2024 using the effective interest method. Consideration allocated to the AstraZeneca TSA services was recognized as collaborative arrangements revenue as such services are provided over the performance period based on the amount to which the Company has a right to invoice. Consideration for the supply of linaclotide API, finished drug product and finished goods under the AstraZeneca CSA was recognized over the performance period as linaclotide API, finished drug product and finished goods were shipped to AstraZeneca. During the year ended December 31, 2021, the Company recognized $0.7 million in collaborative arrangements revenue related to the Amended AstraZeneca Agreement, of which $0.5 million related to royalties and $0.2 million related to AstraZeneca TSA services, and recognized ​ During the year ended December 31, 2020, the Company recognized arrangements revenue related to the Amended AstraZeneca License, of which $0.6 million related to the AstraZeneca TSA services and $0.1 million related to royalties, and recognized $5.5 million of sales of API relating to the supply of linaclotide finished drug product and finished goods under the AstraZeneca CSA. The Company recognized $0.8 million in interest income related to the significant financing component of the Amended AstraZeneca Agreement during the year ended December 31, 2020. ​ During the year ended December 31, 2019, the Company recognized $32.6 million in collaborative arrangements revenue related to the Amended AstraZeneca License, of which $32.4 million related to the delivery of the AstraZeneca License and $0.2 million related to the AstraZeneca TSA services, and recognized $3.0 million of sale of API relating to the supply of linaclotide finished drug product and finished goods under the AstraZeneca CSA. The Company recognized $0.2 million in interest income related to the significant financing component of the Amended AstraZeneca Agreement during the year ended December 31, 2019. ​ Other Collaboration and License Agreements Collaboration and License Option Agreement with Cour Pursuant to the terms of the COUR Collaboration Agreement, the Company made an upfront, non-refundable payment of $6.0 million to COUR during the year ended December 31, 2021, and will pay COUR non-contingent payments and milestone payments totaling $13.5 million in connection with certain development activities and regulatory milestones. After reviewing the data from the Initial Study, if the Company exercises the Option, the Company will pay COUR $35.0 million in exchange for the license. Upon commercialization, COUR will be eligible to receive commercial milestone payments of up to $440.0 million over the term of the agreement and royalties in the high single digits to low double digits percentage of the aggregated annual net sales in the U.S. of products containing CNP-104. ​ Other Agreements Disease Education and Promotional Agreement with Alnylam In August 2019, the Company and Alnylam entered into a disease education and promotional agreement (the “Alnylam Agreement”) for Alnylam’s GIVLAARI for the treatment of AHP. The Alnylam Agreement, as amended, was terminated in June 2021 with an effective termination date of September 30, 2021. Under the terms of the Alnylam Agreement, the Company’s sales force performed disease awareness activities and sales detailing activities for GIVLAARI to gastroenterologists and health care practitioners to whom they detail LINZESS in the first position over the term of the agreement. Pursuant to the terms of the Alnylam Agreement, the Company received service fees, totaling ​ ● performance of disease education activities for AHP and performance of sales details for GIVLAARI (together “Givosiran Education and Promotion Activities”). The Company allocated the service fees to the performance of Givosiran Education and Promotion Activities and recognized collaborative arrangements revenue through December 31, 2020 as the services were performed based on the amount to which the Company had a right to invoice. Royalties are recognized as collaborative arrangements revenue for Givosiran Education and Promotion Activities based on the amount to which the Company has a right to invoice when the associated constraints have been lifted. During the years ended December 31, 2021 and 2020, the Company recognized $2.4 million and $0.8 million, respectively, in collaborative arrangements revenue related to royalties. During the years ended December 31, 2020 and 2019, the Company recognized $3.5 million and $2.0 million, respectively, in collaborative arrangements revenue related to the service fees.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Fair Value of Financial Instruments	6. Fair Value of Financial Instruments The tables below present information about the Company’s assets that are measured at fair value on a recurring basis as of December 31, 2021 and 2020 and indicate the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. In general, fair values determined by Level 1 inputs utilize observable inputs such as quoted prices in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize data points that are either directly or indirectly observable, such as quoted prices for similar instruments in active markets, interest rates and yield curves. Fair values determined by Level 3 inputs utilize unobservable data points in which there is little or no market data, which require the Company to develop its own assumptions for the asset or liability. The Company’s investment portfolio may include fixed income securities that do not always trade on a daily basis. As a result, the pricing services used by the Company apply other available information as applicable through processes such as benchmark yields, benchmarking of like securities, sector groupings and matrix pricing to prepare valuations. In addition, model processes are used to assess interest rate impact and develop prepayment scenarios. These models take into consideration relevant credit information, perceived market movements, sector news and economic events. The inputs into these models may include benchmark yields, reported trades, broker-dealer quotes, issuer spreads and other relevant data. The Company validates the prices provided by its third party pricing services by obtaining market values from other pricing sources and analyzing pricing data in certain instances. The Company periodically invests in certain reverse repurchase agreements, which are collateralized by Government Securities and Obligations for an amount not less than 102% of their principal amount. The Company does not record an asset or liability for the collateral as the Company is not permitted to sell or re-pledge the collateral. The collateral has at least the prevailing credit rating of U.S. Government Treasuries and Agencies. The Company utilizes a third party custodian to manage the exchange of funds and ensure the collateral received is maintained at 102% of the reverse repurchase agreements principal amount on a daily basis. The following tables present the assets and liabilities the Company has measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting Date Using ​ ​ ​ Quoted Prices in Significant Other Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ December 31, ​ Identical Assets ​ Inputs ​ Inputs ​ ​ 2021 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 595,233 ​ $ 595,233 ​ $ — ​ $ — Restricted cash: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 1,735 ​ ​ 1,735 ​ ​ — ​ ​ — Convertible note hedges ​ ​ 1,115 ​ ​ — ​ ​ — ​ ​ 1,115 Total assets measured at fair value ​ $ 598,083 ​ $ 596,968 ​ $ — ​ $ 1,115 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Note hedge warrants ​ $ 1,316 ​ $ — ​ $ — ​ $ 1,316 Total liabilities measured at fair value ​ $ 1,316 ​ $ — ​ $ — ​ $ 1,316 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting Date Using ​ ​ ​ Quoted Prices in Significant Other Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ December 31, ​ Identical Assets ​ Inputs ​ Inputs ​ ​ 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 349,014 ​ $ 349,014 ​ $ — ​ $ — Restricted cash: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ 2,221 ​ 2,221 ​ — ​ — Convertible note hedges ​ ​ 13,065 ​ ​ — ​ ​ — ​ ​ 13,065 Total assets measured at fair value ​ $ 364,300 ​ $ 351,235 ​ $ — ​ $ 13,065 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Note hedge warrants ​ $ 12,088 ​ $ — ​ $ — ​ $ 12,088 Total liabilities measured at fair value ​ $ 12,088 ​ $ — ​ $ — ​ $ 12,088 There were no transfers between fair value measurement levels during each of the years ended December 31, 2021, 2020, and 2019. Cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable, accrued research and development costs, accrued expenses and other current liabilities and current portion of operating lease obligations at December 31, 2021 and 2020 are carried at amounts that approximate fair value due to their short-term maturities. Convertible Note Hedges and Note Hedge Warrants with Respect to 2022 Convertible Notes The Company’s Convertible Note Hedges and the Note Hedge Warrants are recorded as derivative assets and liabilities, respectively, and are classified as Level 3 measurements under the fair value hierarchy. These derivatives are not actively traded and are valued using the Black-Scholes option-pricing model, which requires the use of subjective assumptions. The following inputs were used in the fair market valuation of the Convertible Note Hedges and Note Hedge Warrants as of December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ Year Ended ​ ​ ​ December 31, 2021 ​ December 31, 2020 ​ ​ ​ Convertible Note Hedge ​ Convertible Note Hedge ​ ​ Note Hedges ​ Warrants Note Hedges ​ Warrants Risk-free interest rate (1) ​ ​ 0.2 % ​ 0.4 % ​ 0.1 % ​ 0.1 % Expected term ​ 0.5 ​ 1.0 ​ ​ 1.5 ​ 2.0 ​ Stock price (2) ​ $ 11.66 ​ $ 11.66 ​ $ 11.39 ​ $ 11.39 ​ Strike price (3) ​ $ 14.51 ​ $ 18.82 ​ $ 14.51 ​ $ 18.82 ​ Common stock volatility (4) ​ ​ 27.0 % ​ 32.2 % ​ 46.7 % ​ 50.3 % Dividend yield (5) ​ — % — % — % — % (1) Based on U.S. Treasury yield curve, with terms commensurate with the expected terms of the Convertible Note Hedges and the Note Hedge Warrants. (2) The closing price of the Company’s Class A Common Stock on the last trading days of the years ended December 31, 2021 and 2020, respectively. (3) As per the respective agreements for the Convertible Note Hedges and Note Hedge Warrants. (4) Expected volatility based on historical volatility of the Company’s Class A Common Stock. (5) The Company has not paid and does not anticipate paying cash dividends on its shares of common stock in the foreseeable future; therefore, the expected dividend yield is assumed to be zero . ​ The Convertible Note Hedges and the Note Hedge Warrants are recorded at fair value at each reporting date and changes in fair value are recorded in other (expense) income, net within the Company's consolidated statements of income. The following table reflects the change in the Company's Level 3 Convertible Note Hedges and Note Hedge Warrants from December 31, 2019 through December 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible ​ Note Hedge ​ Note Hedges Warrants Balance at December 31, 2019 ​ $ 31,366 ​ $ (24,260) Change in fair value, recorded as a component of (loss) gain on derivatives ​ ​ (18,301) ​ ​ 12,172 Balance at December 31, 2020 ​ $ 13,065 ​ $ (12,088) Change in fair value, recorded as a component of (loss) gain on derivatives ​ ​ (11,950) ​ ​ 10,772 Balance at December 31, 2021 ​ $ 1,115 ​ $ (1,316) Convertible Senior Notes In June 2015, the Company issued $335.7 million aggregate principal amount of its 2022 Convertible Notes. In August 2019, the Company issued $200.0 million aggregate principal amount of its 2024 Convertible Notes and $200.0 million aggregate principal amount of its 2026 Convertible Notes, and used a portion of the proceeds from such issuances to repurchase $215.0 million aggregate principal amount of its 2022 Convertible Notes. The Company separately accounted for the liability and equity components of each of the 2022 Convertible Notes, 2024 Convertible Notes, and 2026 Convertible Notes, by allocating the proceeds between the liability component and equity component (Note 10). The fair value of the respective convertible senior notes, which differs from their carrying value, is influenced by interest rates, the price of the Company’s Class A Common Stock and the volatility thereof, and the prices for the respective convertible senior notes observed in market trading, which are Level 2 inputs. The estimated fair value of the 2022 Convertible Notes was $125.2 million and $130.2 million as of December 31, 2021 and 2020, respectively. The estimated fair value of the 2024 Convertible Notes was $221.9 million and $222.3 million as of December 31, 2021 and 2020, respectively. The estimated fair value of the 2026 Convertible Notes was $227.2 million and $224.1 million as of December 31, 2021 and 2020, respectively. Capped Calls with Respect to 2024 Convertible Notes and 2026 Convertible Notes ​ In connection with the issuance of the 2024 Convertible Notes and the 2026 Convertible Notes, the Company entered into the Capped Calls with certain financial institutions. The Capped Calls cover 29,867,480 shares of Class A Common Stock (subject to anti-dilution and certain other adjustments), which is the same number of shares of Class A Common Stock that initially underlie the 2024 Convertible Notes and the 2026 Convertible Notes. The Capped Calls have an initial strike price of approximately $13.39 per share, which corresponds to the initial conversion price of the 2024 Convertible Notes and the 2026 Convertible Notes, and have a cap price of approximately $17.05 per share (Note 10). The strike price and cap price are subject to anti-dilution adjustments generally similar to those applicable to the 2024 Convertible Notes and the 2026 Convertible Notes. These instruments meet the conditions outlined in ASC 815, to be classified in stockholders’ equity (deficit) and are not subsequently remeasured as long as the conditions for equity classification continue to be met (Note 10).

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Leases	7. Leases Effective January 1, 2019, the Company adopted ASC 842 using the optional transition method ​ The Company’s office lease and vehicle lease require letters of credit to secure the Company’s obligations under the lease agreements totaling ​ Lease cost is recognized on a straight-line basis over the lease term. The components of lease cost for the years ended December 31, 2021, 2020 and 2019 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ Operating lease cost (1) ​ $ 2,520 ​ $ 2,530 ​ $ 16,452 ​ Variable lease payments ​ ​ — ​ ​ — ​ ​ 1,526 ​ Short-term lease cost ​ ​ 960 ​ ​ 1,420 ​ ​ 1,512 ​ Total lease cost ​ $ 3,480 ​ $ 3,950 ​ $ 19,490 ​ (1) Operating lease cost is presented net of $0.3 million of sublease income for the year ended December 31, 2019 related to a sublease agreement between Ironwood and Cyclerion executed upon Separation. The sublease agreement terminated in May 2019. ​ Supplemental information related to leases for the periods reported is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ ​ Right-of-use assets obtained in exchange for new operating lease upon adoption of ASC 842 (in thousands) ​ ​ $ — ​ ​ $ — ​ ​ $ 88,299 ​ ​ Adjustment to right-of-use assets as a result of the lease modification upon Separation (in thousands) ​ ​ ​ — ​ ​ ​ — ​ ​ ​ (40,427) ​ ​ Adjustment to right-of-use assets as a result of the termination of the Binney Street Lease (in thousands) ​ ​ ​ — ​ ​ ​ — ​ ​ ​ (34,440) ​ ​ Right-of-use assets obtained in exchange for new operating lease liabilities upon execution of Summer Street Lease (in thousands) ​ ​ ​ — ​ ​ ​ — ​ ​ ​ 18,452 ​ ​ Cash paid for amounts included in the measurement of lease liabilities (in thousands) ​ ​ $ 3,128 ​ ​ $ 1,146 ​ ​ $ 18,598 ​ ​ Weighted-average remaining lease term of operating leases (in years) ​ ​ ​ 8.3 ​ ​ ​ 9.3 ​ ​ ​ 10.2 ​ ​ Weighted-average discount rate of operating leases ​ ​ ​ 5.8 % ​ ​ 5.8 % ​ ​ 5.8 % ​ ​ Future minimum lease payments under non-cancelable operating leases as of December 31, 2021 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 ​ $ 3,129 2023 ​ ​ 3,065 2024 ​ ​ 3,126 2025 ​ 3,189 2026 ​ 3,252 2027 and thereafter ​ ​ 11,603 Total future minimum lease payments ​ ​ 27,364 Less: present value adjustment ​ ​ (5,753) Operating lease liabilities ​ ​ 21,611 Less: current portion of operating lease liabilities ​ ​ (3,127) Operating lease liabilities, net of current portion ​ $ 18,484 ​ Summer Street Lease (current headquarters) ​ In June 2019, the Company entered into a non-cancelable operating lease (the “Summer Street Lease”) for approximately 39,000 square feet of office space on the 23 rd ​ At lease inception, the Company recorded a right-of-use asset and a lease liability using an incremental borrowing rate of 5.8%. At December 31, 2021, the balances of the right-of-use asset and operating lease liability were $15.3 million and $21.5 million, respectively. At December 31, 2020, the balances of the right-of-use asset and operating lease liability were $16.6 million and $23.2 million, respectively. ​ Lease costs related to the Summer Street Lease recorded during the years ended December 31, 2021, 2020 and 2019 were $2.5 million, $2.5 million and $1.5 million, respectively. ​ Binney Street Lease (prior headquarters) ​ The Company rented office space at 301 Binney Street, Cambridge, Massachusetts under a non-cancelable operating lease entered into in January 2007, as amended (“Binney Street Lease”) through October 2019. ​ On April 1, 2019, the Company modified the Binney Street Lease to reduce its leased premises to approximately 108,000 rentable square feet of office space on the first and third floors. The surrendered portion of approximately 114,000 rentable square feet on the first and second floor of the building was subsequently occupied by Cyclerion under a direct lease between Cyclerion and the Binney Street landlord. As a result of the modification, the Company adjusted the value of its right-of-use asset and operating lease liability using an incremental borrowing rate of approximately 5.1%, and recognized a gain of approximately $3.2 million, which was recorded as a reduction to operating expenses on its consolidated statement of operations. The Company elected to determine the proportionate reduction in the right-of-use asset based on the reduction to the lease liability. ​ As of January 1, 2019, in conjunction with the adoption of ASC 842, the Company recorded a right-of-use asset of approximately $87.7 million and a lease liability of approximately $94.3 million associated with the Binney Street Lease. ​ On June 11, 2019, the Company entered into a lease termination agreement (the “Lease Termination”) with the Binney Street landlord to terminate the Company’s lease for approximately 108,000 square feet of office space. The Lease Termination was effective during the fourth quarter of 2019 in exchange for an approximately $9.0 million payment. The Lease Termination was accounted for as a lease modification that reduces the term of the existing lease and the Company adjusted the value of its right-of-use asset and operating lease liability using an incremental borrowing rate of approximately 4.0%. ​ Lease cost related to the Binney Street Lease recorded during the year ended December 31, 2019 was approximately $16.3 million, net of sublease income of approximately $0.3 million.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Property and Equipment	8. Property and Equipment Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 2020 Software ​ $ 5,667 ​ $ 8,615 ​ Leasehold improvements ​ 7,407 ​ 7,407 ​ Laboratory equipment ​ 1,327 ​ 1,898 ​ Furniture and fixtures ​ 1,517 ​ 1,517 ​ Computer and office equipment ​ 1,285 ​ 1,297 ​ Total property and equipment ​ 17,203 ​ 20,734 ​ Less accumulated depreciation and amortization ​ (9,628) ​ (11,805) ​ Total property and equipment, net ​ $ 7,575 ​ $ 8,929 ​ ​ Depreciation expense of property and equipment was $1.5 million, $2.3 million and $5.6 million for the years ended December 31, 2021, 2020 and 2019, respectively. During the year ended December 31, 2020, the Company recorded $1.2 million, in restructuring expenses in its consolidated statement of income related to the impairment of certain fixed assets as a result of its decision to discontinue IW-3718 development.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Accrued Expenses and Other Current Liabilities	9. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 2020 Accrued compensation and benefits ​ $ 16,653 ​ ​ 13,413 ​ Restructuring liabilities ​ ​ 462 ​ 10,510 ​ Stock repurchase ​ ​ 3,009 ​ ​ — ​ Other ​ 3,442 ​ ​ 2,563 ​ Total accrued expenses and other current liabilities ​ $ 23,566 ​ $ 26,486 ​ ​ As of December 31, 2021, other accrued expenses of $3.4 million included $2.7 million of uninvoiced vendor liabilities, $0.3 million of accrued interest and $0.2 million of state income taxes payable. ​ As of December 31, 2020, other accrued expenses of $2.6 million included $2.1 million of uninvoiced vendor liabilities and $0.3 million of accrued interest.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Notes Payable	10. Notes Payable 2.25% Convertible Senior Notes due 2022 In June 2015, the Company issued $335.7 million aggregate principal amount of the 2022 Convertible Notes. The Company received net proceeds of $324.0 million from the sale of the 2022 Convertible Notes, after deducting fees and expenses of $11.7 million. The Company used $21.1 million of the net proceeds from the sale of the 2022 Convertible Notes to pay the net cost of the Convertible Note Hedges (after such cost was partially offset by the proceeds to the Company from the sale of the Note Hedge Warrants), as described below. The 2022 Convertible Notes are governed by an indenture (the “2022 Indenture”) between the Company and U.S. Bank National Association, as trustee (the “Trustee”). The 2022 Convertible Notes are senior unsecured obligations and bear cash interest at the annual rate of 2.25%, payable on June 15 and December 15 of each year. The 2022 Convertible Notes will mature on June 15, 2022, unless earlier converted or repurchased. The Company held the option to determine settlement method through payment or delivery, as the case may be, of cash, shares of the Company’s Class A Common Stock, or a combination of cash and shares of Class A Common Stock (subject to, and in accordance with, the settlement provisions of the 2022 Indenture). The Company has elected to settle conversions of the 2022 Convertible Notes through cash payment equal to the principal value and shares of Class A Common Stock for the conversion premium, if any. The initial conversion rate for the 2022 Convertible Notes was 60.3209 shares of Class A Common Stock (subject to adjustment as provided for in the 2022 Indenture) per $1,000 principal amount of the 2022 Convertible Notes, which was equal to an initial conversion price of approximately $16.58 per share and 20,249,665 shares. In connection with the Separation, in April 2019, the conversion rate under the 2022 Indenture was adjusted to equal 68.9172 shares of Class A Common Stock per $1,000 principal amount of the 2022 Convertible Notes, which is equal to an adjusted conversion price of approximately $14.51 per share and 23,135,435 shares. ​ Holders of the 2022 Convertible Notes had the right to convert their 2022 Convertible Notes at their option at any time prior to the close of business on the business day immediately preceding December 15, 2021 upon the occurrence of certain circumstances and no such conversions occurred. On or after December 15, 2021, until the close of business on the second scheduled trading day immediately preceding June 15, 2022, holders may convert their 2022 Convertible Notes, in multiples of $1,000 principal amount, at the option of the holder. Upon the occurrence of certain fundamental changes, as described in the 2022 Indenture, holders of the 2022 Convertible Notes may require the Company to repurchase for cash all or part of their 2022 Convertible Notes at a repurchase price equal to 100% of the principal amount of the 2022 Convertible Notes to be repurchased, plus accrued and unpaid interest. If a make-whole fundamental change, as described in the 2022 Indenture, occurs and a holder elects to convert its 2022 Convertible Notes in connection with such make-whole fundamental change, such holder may be entitled to an increase in the conversion rate as described in the 2022 Indenture. The 2022 Indenture does not contain any financial covenants or restrict the Company’s ability to repurchase the Company’s securities, pay dividends or make restricted payments in the event of a transaction that substantially increases the Company’s level of indebtedness. The 2022 Indenture provides for customary events of default. In the case of an event of default with respect to the 2022 Convertible Notes arising from specified events of bankruptcy or insolvency, all outstanding 2022 Convertible Notes will become due and payable immediately without further action or notice. If any other event of default with respect to the 2022 Convertible Notes under the 2022 Indenture occurs or is continuing, the Trustee or holders of at least 25% in aggregate principal amount of the then outstanding 2022 Convertible Notes may declare the principal amount of the 2022 Convertible Notes to be immediately due and payable. Notwithstanding the foregoing, the 2022 Indenture provides that, upon the Company’s election, and for up to 180 days, the sole remedy for an event of default relating to certain failures by the Company to comply with certain reporting covenants in the 2022 Indenture consists exclusively of the right to receive additional interest on the 2022 Convertible Notes. In accordance with accounting guidance for debt with conversion and other options, the Company separately accounted for the liability and equity components of the 2022 Convertible Notes by allocating the proceeds between the liability component and the embedded conversion option, or equity component, due to the Company's ability to settle the 2022 Convertible Notes in cash, its Class A Common Stock, or a combination of cash and Class A Common Stock at the option of the Company. The carrying amount of the liability component was calculated by measuring the fair value of a similar liability that does not have an associated conversion feature. The equity component of the 2022 Convertible Notes was recognized as a debt discount and represents the difference between the gross proceeds from the issuance of the 2022 Convertible Notes and the fair value of the liability component of the 2022 Convertible Notes on their respective dates of issuance. The debt discount is amortized to interest expense using the effective interest method over seven years, or the expected life of the 2022 Convertible Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. ​ In connection with the issuance of the 2024 Convertible Notes and the 2026 Convertible Notes in August 2019, the Company repurchased $215.0 million aggregate principal amount of the 2022 Convertible Notes. The 2022 Convertible Notes were repurchased at a premium totaling $227.3 million. The Company recognized a loss on extinguishment of debt of $23.4 million during the year ended December 31, 2019 related to the prepayment premium and proportional write-off of the 2022 Convertible Notes unamortized debt issuance costs and unamortized debt discount. Additionally, the repurchase resulted in a reduction to additional paid-in capital of $27.0 million during the year ended December 31, 2019 related to the equity component of the 2022 Convertible Notes. ​ 0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 ​ In August 2019, the Company issued $200.0 million aggregate principal amount of the 2024 Convertible Notes and $200.0 million aggregate principal amount of the 2026 Convertible Notes. The Company received net proceeds of $391.0 million from the sale of the 2024 Convertible Notes and 2026 Convertible Notes, after deducting fees and expenses of $9.0 million. The Company used $25.2 million of the net proceeds from the sale of the 2024 Convertible Notes and 2026 Convertible Notes to pay the cost of the Capped Calls, as described below. For purposes of this section, “Notes” refer to the 2024 Convertible Notes and the 2026 Convertible Notes, collectively. ​ The 2024 Convertible Notes and 2026 Convertible Notes were issued by the Company on August 12, 2019, pursuant to separate Indentures, each dated as of such date (each an “Indenture” and together the “Indentures”), between the Company and the Trustee. The 2024 Convertible Notes bear cash interest at the annual rate of 0.75% and the 2026 Convertible Notes bear cash interest at the annual rate of 1.50%, each payable on June 15 and December 15 of each year. The 2024 Convertible Notes will mature on June 15, 2024 and the 2026 Convertible Notes will mature on June 15, 2026, unless earlier converted or repurchased. The Company will settle conversions of the 2024 Convertible Notes and 2026 Convertible Notes through payment or delivery, as the case may be, of cash, shares of the Company’s Class A Common Stock or a combination of cash and shares of Class A Common Stock, at the Company’s option (subject to, and in accordance with, the settlement provisions of the applicable Indenture). The initial conversion rate for each of the 2024 Convertible Notes and the 2026 Convertible Notes is 74.6687 shares of Class A Common Stock (subject to adjustment as provided for in the applicable Indenture) per $1,000 principal amount of the 2024 Convertible Notes and 2026 Convertible Notes, which is equal to an initial conversion price of approximately $13.39 per share. ​ Holders of the 2024 Convertible Notes and 2026 Convertible Notes may convert their Notes at their option at any time prior to the close of business on the business day immediately preceding December 15, 2023, with respect to the 2024 Convertible Notes, and December 15, 2025, with respect to the 2026 Convertible Notes, in multiples of $1,000 principal amount, only under the following circumstances: ​ ● during any calendar quarter commencing after the calendar quarter ending on December 31, 2019 (and only during such calendar quarter), if the last reported sale price of Class A Common Stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price for the Notes on each applicable trading day; ​ ● during the five business day period after any five consecutive trading day period (the “measurement period”) in which the “trading price” (as defined in each Indenture) per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of Class A Common Stock and the conversion rate for the Notes on each such trading day; or ​ ● upon the occurrence of specified corporate events described in each Indenture. ​ On or after December 15, 2023, with respect to the 2024 Convertible Notes, and December 15, 2025, with respect to the 2026 Convertible Notes, until the close of business on the second scheduled trading day immediately preceding the applicable maturity date, the holders of the Notes may convert their Notes, in multiples of $1,000 principal amount, regardless of the foregoing conditions. ​ Upon the occurrence of fundamental changes, as described in the Indentures, prior to the maturity date of the respective Notes, holders of such Notes may require the Company to repurchase for cash all or a portion of their Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest. If a make-whole fundamental change, as described in the Indentures, occurs and a holder elects to convert its Notes in connection with such make-whole fundamental change, such holder may be entitled to an increase in the conversion rate as described in the Indentures. ​ The Indentures do not contain any financial covenants or restrict the Company’s ability to repurchase the Company’s securities, pay dividends or make restricted payments in the event of a transaction that substantially increases the Company’s level of indebtedness. The Indentures provide for customary events of default. In the case of an event of default with respect to a series of Notes arising from specified events of bankruptcy or insolvency, all outstanding Notes of such series will become due and payable immediately without further action or notice. If any other event of default with respect to a series of Notes under the relevant Indenture occurs or is continuing, the Trustee or holders of at least 25% in aggregate principal amount of the then outstanding Notes of such series may declare the principal amount of such Notes to be immediately due and payable. ​ In accordance with accounting guidance for debt with conversion and other options, the Company separately accounted for the liability and equity components of the 2024 Convertible Notes and the 2026 Convertible Notes by allocating the proceeds between the liability components and the embedded conversion options, or equity components, due to the Company’s ability to settle the 2024 Convertible Notes and the 2026 Convertible Notes in cash, its Class A Common Stock, or a combination of cash and Class A Common Stock at the option of the Company. The carrying amount of the respective liability components were calculated by measuring the fair value of a similar liability that does not have an associated conversion feature. The respective equity components of the 2024 Convertible Notes and the 2026 Convertible Notes were recognized as a debt discount and represent the difference between the gross proceeds from the issuance of the 2024 Convertible Notes and 2026 Convertible Notes and the fair value of the liability of the 2024 Convertible Notes and 2026 Convertible Notes on their respective dates of issuance. The debt discount is amortized to interest expense using the effective interest method over approximately five ​ The Company’s outstanding balances for the convertible senior notes as of December 31, 2021 and 2020 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2021 ​ 2020 ​ Liability component: ​ ​ ​ ​ ​ ​ Principal: ​ ​ ​ ​ ​ 2022 Convertible Notes $ 120,699 ​ $ 120,699 ​ 2024 Convertible Notes ​ 200,000 ​ ​ 200,000 ​ 2026 Convertible Notes ​ 200,000 ​ ​ 200,000 ​ Less: unamortized debt discount ​ (61,641) ​ ​ (83,900) ​ Less: unamortized debt issuance costs ​ (4,867) ​ ​ (6,543) ​ Net carrying amount $ 454,191 ​ $ 430,256 ​ Equity component: ​ ​ ​ ​ ​ ​ 2022 Convertible Notes ​ 19,807 ​ ​ 19,807 ​ 2024 Convertible Notes ​ 41,152 ​ ​ 41,152 ​ 2026 Convertible Notes ​ 51,350 ​ ​ 51,350 ​ Total equity component $ 112,309 ​ $ 112,309 ​ ​ In connection with the issuance of the 2022 Convertible Notes, the Company incurred $11.7 million of debt issuance costs, which primarily consisted of initial purchasers’ discounts and legal and other professional fees. The Company allocated these costs to the liability and equity components based on the allocation of the proceeds. The portion of these costs allocated to the equity components totaling $4.0 million were recorded as a reduction to additional paid-in capital upon issuance. The portion of these costs allocated to the liability components totaling $7.7 million were recorded as a reduction in the carrying value of the debt on the consolidated balance sheet and are amortized to interest expense using the effective interest method over the expected life of the 2022 Convertible Notes. In connection with the partial repurchase of the 2022 Convertible Notes, the Company recorded a loss on extinguishment of debt of $23.4 million, of which $2.8 million related to the initial debt issuance costs, during the year ended December 31, 2019. The Company determined the expected life of the 2022 Convertible Notes was equal to their seven-year term. The effective annual interest rate on the liability components of the 2022 Convertible Notes for the period from the date of issuance through June 30, 2019 was 9.34%. From the date of the partial repurchase of the 2022 Convertible Notes in August 2019 through December 31, 2021, the effective annual interest rate on the liability component of the 2022 Convertible Notes was 10.1%. In connection with the issuance of the 2024 Convertible Notes and the 2026 Convertible Notes, the Company incurred $9.0 million of debt issuance costs, which primarily consisted of initial purchaser’s discounts and legal and other professional fees. The Company allocated these costs to the liability and equity components based on the allocation of the proceeds. The portion of these costs allocated to the equity components totaling $2.1 million were recorded as a reduction to additional paid-in capital. The portion of these costs allocated to the liability components totaling $6.9 million were recorded as a reduction in the carrying value of the debt on the consolidated balance sheet and are amortized to interest expense using the effective interest method over the expected lives of the 2024 Convertible Notes and the 2026 Convertible Notes. ​ The Company determined the expected life of the 2024 Convertible Notes and the 2026 Convertible Notes was equal to their approximately five ​ The following table sets forth total interest expense recognized related to convertible senior notes during the years ended December 31, 2021, 2020, and 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 ​ 2019 Contractual interest expense ​ $ 7,216 ​ $ 7,216 ​ $ 7,361 Amortization of debt issuance costs ​ ​ 1,678 ​ ​ 1,462 ​ ​ 1,190 Amortization of debt discount ​ ​ 22,256 ​ ​ 20,800 ​ ​ 17,683 Total interest expense ​ $ 31,150 ​ $ 29,478 ​ $ 26,234 ​ Future minimum payments under the convertible senior notes as of December 31, 2021, are as follows (in thousands): ​ ​ ​ ​ ​ ​ 2022 ​ $ 126,557 ​ 2023 ​ ​ 4,500 ​ 2024 ​ ​ 203,750 ​ 2025 ​ ​ 3,000 ​ 2026 ​ ​ 201,500 ​ Total future minimum payments under the convertible senior notes ​ 539,307 ​ Less: amounts representing interest ​ ​ (18,608) ​ Less: unamortized debt discount ​ ​ (61,641) ​ Less: unamortized debt issuance costs ​ ​ (4,867) ​ Convertible senior notes balance ​ $ 454,191 ​ ​ ​ As of December 31, 2021, $120.7 million in aggregate principal amount of the 2022 Convertible Notes was due within the next 12 months and is classified as current liabilities on the Company’s consolidated balance sheets. ​ Convertible Note Hedge and Note Hedge Warrant Transactions with Respect to 2022 Convertible Notes To minimize the impact of potential dilution to the Company's Class A common stockholders upon conversion of the 2022 Convertible Notes, the Company entered into the Convertible Note Hedges covering 20,249,665 shares of the Company’s Class A Common Stock in connection with the issuance of the 2022 Convertible Notes. The Convertible Note Hedges had an initial exercise price of $16.58 per share, subject to adjustment upon the occurrence of certain corporate events or transactions, and are exercisable if the 2022 Convertible Notes are converted. In connection with the adjustment to the conversion rate of the 2022 Convertible Notes related to the Separation in April 2019, the exercise price of the Convertible Note Hedges was adjusted to $14.51 per share and the number of shares underlying the Convertible Note Hedges was increased to 23,135,435 shares. If upon conversion of the 2022 Convertible Notes, the price of the Company’s Class A Common Stock is above the exercise price of the Convertible Note Hedges, the counterparties are obligated to deliver shares of the Company’s Class A Common Stock and/or cash with an aggregate value approximately equal to the difference between the price of the Company’s Class A Common Stock at the conversion date and the exercise price, multiplied by the number of shares of the Company’s Class A Common Stock related to the Convertible Note Hedge being exercised. Concurrently with entering into the Convertible Note Hedges, the Company sold Note Hedge Warrants to the Convertible Note Hedge counterparties to acquire 20,249,665 shares of the Company’s Class A Common Stock, subject to customary anti-dilution adjustments. The strike price of the Note Hedge Warrants was initially $21.50 per share, subject to adjustment, and such warrants are exercisable over the 150 trading day period beginning on September 15, 2022. In connection with the Separation in April 2019, the exercise price was adjusted to $18.82 per share and the number of shares underlying the Note Hedge Warrants was increased to 23,135,435 shares. The Note Hedge Warrants could have a dilutive effect on the Class A Common Stock to the extent that the market price per share of the Company’s Class A Common Stock exceeds the applicable strike price of such warrants. The Convertible Note Hedges and the Note Hedge Warrants are separate transactions entered into by the Company and are not part of the terms of the 2022 Convertible Notes. Holders of the Convertible Note Hedges and the Note Hedge Warrants do not have any rights with respect to the 2022 Convertible Notes. The Company paid $91.9 million for the Convertible Note Hedges and received $70.8 million for the Note Hedge Warrants, resulting in a net cost to the Company of $21.1 million. In August 2019, concurrently with the repurchase of $215.0 million aggregate principal amount of the 2022 Convertible Notes, the Company terminated the respective portion of the Convertible Note Hedges and Note Hedge Warrants. The Company received $3.2 million of termination payments from the counterparties of the Convertible Note Hedges and Note Hedge Warrants. ​ The Convertible Note Hedges and Note Hedge Warrants are accounted for as derivative assets and liabilities, respectively, in accordance with ASC 815, and are remeasured to fair value at each reporting date (Note 6). As of December 31, 2021, the Convertible Note Hedges and Note Hedge Warrants were classified as current assets and current liabilities, respectively, on the Company’s consolidated balance sheets. As of December 31, 2020, the Convertible Note Hedges and Note Hedge Warrants were classified as non-current assets and non-current liabilities, respectively, on the Company’s consolidated balance sheets. Capped Calls with Respect to 2024 Convertible Notes and 2026 Convertible Notes ​ To minimize the impact of potential dilution to the Company’s Class A common stockholders upon conversion of the 2024 Convertible Notes and the 2026 Convertible Notes, the Company entered into separate Capped Calls in connection with the issuance of the 2024 Convertible Notes and the 2026 Convertible Notes. The Company paid the counterparties $25.2 million to enter into the Capped Calls. ​ The Capped Calls have an initial strike price of approximately $13.39 per share, which corresponds to the initial conversion price of the 2024 Convertible Notes and the 2026 Convertible Notes and is subject to anti-dilution adjustments generally similar to those applicable to the 2024 Convertible Notes and the 2026 Convertible Notes. The Capped Calls have a cap price of approximately $17.05 per share, subject to certain adjustments. The Capped Calls cover 29,867,480 shares of Class A Common Stock (subject to anti-dilution and certain other adjustments), which is the same number of shares of Class A Common Stock that initially underlie the 2024 Convertible Notes and the 2026 Convertible Notes. ​ The Capped Calls are expected generally to reduce the potential dilution to the Class A Common Stock upon conversion of the 2024 Convertible Notes and the 2026 Convertible Notes in the event that the market price per share of Class A Common Stock is greater than the strike price of the Capped Calls as adjusted pursuant to the anti-dilution adjustments. If, however, the market price per share of Class A Common Stock exceeds the cap price of the Capped Calls, there would nevertheless be dilution upon conversion of the 2024 Convertible Notes and the 2026 Convertible Notes to the extent that such market price exceeds the cap price of the Capped Calls. ​ The Capped Calls are separate transactions entered into by and between the Company and the Capped Calls counterparties and are not part of the terms of the 2024 Convertible Notes or the 2026 Convertible Notes. Holders of the 2024 Convertible Notes and the 2026 Convertible Notes do not have any rights with respect to the Capped Calls. The Company recorded a reduction to additional paid-in capital of $25.0 million during the year ended December 31, 2019 related to the premium payments for the Capped Calls. Additionally, the Company recorded a $0.2 million reduction to equity related to transaction costs incurred in connection with the Capped Calls during the year ended December 31, 2019. These instruments meet the conditions outlined in ASC 815 to be classified in stockholders’ equity and are not subsequently remeasured as long as the conditions for equity classification continue to be met.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Commitments and Contingencies	11. Commitments and Contingencies Commitments with AbbVie The Company and AbbVie are jointly obligated to make minimum purchases of linaclotide API for the territories covered by the Company’s collaboration with AbbVie for North America. Currently, AbbVie fulfills all such minimum purchase commitments. Under the collaboration agreement with AbbVie for North America, the Company shares all development and commercialization costs related to linaclotide in the U.S. with AbbVie. The actual amounts that the Company pays to AbbVie or that AbbVie pays to the Company will depend on numerous factors outside of the Company’s control, including the success of certain clinical development efforts with respect to linaclotide, the content and timing of decisions made by the regulators, the reimbursement and competitive landscape around linaclotide and the Company’s other product candidates, and other factors. Other Funding Commitments As of December 31, 2021, the Company has ongoing studies in various pre-clinical and clinical trial stages. The Company’s most significant clinical trial expenditures are to contract research organizations. These contracts are generally cancellable, with notice, at the Company’s option and do not have any significant cancellation penalties. Guarantees As permitted under Delaware law, the Company indemnifies its directors and certain of its officers for certain events or occurrences while such director or officer is, or was, serving at the Company’s request in such capacity. The maximum potential amount of future payments the Company could be required to make is unlimited; however, the Company has directors’ and officers’ insurance coverage that is intended to limit its exposure and enable it to recover a portion of any future amounts paid. The Company enters into certain agreements with other parties in the ordinary course of business that contain indemnification provisions. These typically include agreements with business partners, contractors, landlords, clinical sites and customers. Under these provisions, the Company generally indemnifies and holds harmless the indemnified party for losses suffered or incurred by the indemnified party as a result of the Company’s activities. These indemnification provisions generally survive termination of the underlying agreements. The maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited. However, to date the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. As a result, the estimated fair value of these obligations is minimal. Accordingly, the Company did not have any liabilities recorded for these obligations as of December 31, 2021 and 2020. Litigation From time to time, the Company is involved in various legal proceedings and claims, either asserted or unasserted, which arise in the ordinary course of business. While the outcome of these other claims cannot be predicted with certainty, management does not believe that the outcome of any of these ongoing legal matters, individually and in aggregate, will have a material adverse effect on the Company’s consolidated financial statements. In January 2020, the Company and AbbVie entered into settlement agreements with Sandoz Inc. and Teva Pharmaceuticals, USA resolving patent litigation brought in response to the last outstanding abbreviated new drug applications seeking approval to market generic versions of LINZESS prior to the expiration of the Company’s and AbbVie’s applicable patents. In May 2021, the Company and AbbVie entered into a settlement agreement with Teva, under which the Company and AbbVie will grant Teva a license to market a generic version of 72 mcg LINZESS beginning March 31, 2029 (subject to FDA approval), unless certain limited circumstances, customary for settlement agreements of this nature, occur. With this settlement agreement, the Company and AbbVie have settled with the filers of all known ANDAs to date seeking approval to market generic versions of LINZESS.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Stockholders' Equity	12. Stockholders’ Equity Preferred Stock The Company’s preferred stock may be issued from time to time in one or more series, with each such series to consist of such number of shares and to have such terms as adopted by the board of directors. Authority is given to the board of directors to determine and fix such voting powers, full or limited, or no voting powers, and such designations, preferences and relative participating, optional or other special rights, and qualifications, limitation or restrictions thereof, including without limitation, dividend rights, conversion rights, redemption privileges and liquidation preferences. Common Stock The Company has one class of common stock (“Class A Common Stock”). Class A Common Stock is entitled to one vote per share. The Company has reserved, out of its authorized but unissued shares of Class A Common Stock, sufficient shares to effect the conversion of the convertible senior notes and the Note Hedge Warrants pursuant to the terms thereof (Note 10). The Company’s shareholders are entitled to dividends if and when declared by the board of directors. Share Repurchase Program ​ In May 2021, the Company’s Board of Directors authorized a program to repurchase up to $150.0 million of the Company’s Class A Common Stock. Unless it is terminated or suspended prior to its expiration, the share repurchase program will remain in effect until December 31, 2022. The timing and amount of any repurchases will be determined based on market conditions, stock price and other factors. The share repurchase program may be modified, suspended or discontinued at any time without notice. Repurchases may be made through a variety of methods, including open market purchases, privately negotiated transactions, block trades, exchange transactions, accelerated share repurchase transactions, or any combination of such methods. All share repurchases made under the share repurchase program will be retired. ​ During the year ended December 31, 2021, the Company repurchased 2.4 million shares of Class A common stock for an aggregate of $27.1 million. The Company expects to fund further repurchases through a combination of cash on hand and cash generated by operations. As of December 31, 2021, the aggregate remaining value of shares that may be repurchased under the repurchase program was $122.9 million.

Employee Stock Benefit Plans

Employee Stock Benefit Plans	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Employee Stock Benefit Plans	13. Employee Stock Benefit Plans The Company has several share-based compensation plans under which stock options, RSAs, RSUs, and other share-based awards are available for grant to employees, officers, directors and consultants of the Company. ​ The following table summarizes share-based compensation expense by award type (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Stock options ​ $ 3,154 ​ $ 7,680 ​ $ 12,526 ​ Time-based restricted stock units ​ ​ 14,539 ​ ​ 18,624 ​ ​ 15,488 ​ Performance-based restricted stock units ​ 1,295 ​ 2,190 ​ — ​ Restricted stock awards ​ 2,684 ​ 1,886 ​ 2,095 ​ Employee stock purchase plan ​ 419 ​ 722 ​ 1,115 ​ Stock awards ​ 190 ​ 73 ​ 54 ​ Total share-based compensation expense ​ $ 22,281 ​ $ 31,175 ​ $ 31,278 ​ ​ The following table summarizes the share-based compensation expense reflected in the consolidated statements of income (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Share-based compensation expense: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 4,849 ​ $ 5,569 ​ $ 6,343 ​ Selling, general and administrative ​ 17,323 ​ 23,825 ​ 24,281 ​ Restructuring expenses ​ ​ 109 ​ ​ 1,781 ​ ​ 654 ​ Total share-based compensation expense ​ $ 22,281 ​ $ 31,175 ​ $ 31,278 ​ ​ Restructuring expenses include modifications to share-based awards held by employees impacted by various workforce reductions (Note 17). In April 2019, in connection with the Separation, all outstanding share-based payment awards were modified in accordance with the equity conversion-related provisions of the employee matters agreement with Cyclerion. No share-based compensation expense was recognized in connection with these modifications. Additionally, modifications with respect to the Company’s ESPP were made due to the change in share price as a result of the Separation. As a result of the modification to the ESPP, the Company recorded $0.3 million of share-based compensation expense for the year ended December 31, 2019. ​ Stock Benefit Plans As of December 31, 2021, the Company has the following active stock benefit plans pursuant to which awards are currently outstanding: the 2019 Equity Incentive Plan (the “2019 Equity Plan”), the Amended and Restated 2010 Employee Stock Purchase Plan (the “2010 Purchase Plan”) and the Amended and Restated 2010 Employee, Director, and Consultant Equity Incentive Plan (the “2010 Equity Plan”). At December 31, 2021, there were 13,344,791 shares available for future grant under the 2019 Equity Plan and the 2010 Purchase Plan. 2019 Equity Plan During 2019, the Company’s stockholders approved the 2019 Equity Plan under which stock options, RSAs, RSUs, and other stock-based awards may be granted to employees, officers, directors, or consultants of the Company. Under the 2019 Equity Plan, 10,000,000 shares of Class A Common Stock were initially reserved for issuance. Awards that are returned to the 2010 Equity Plan as a result of their expiration, cancellation, termination or repurchase are automatically made available for issuance under the 2019 Equity Plan. Awards that expire, cancel, terminate, or are repurchased under the 2019 Equity Plan will no longer be available for future grant. As of December 31, 2021, 8,773,291 shares were available for future grant under the 2019 Equity Plan. ​ 2010 Purchase Plan During 2010, the Company’s stockholders approved the 2010 Purchase Plan, which gives eligible employees the right to purchase shares of common stock at the lower of 85% of the fair market value on the first or last day of an offering period. Each offering period is six months. There were 400,000 shares of common stock initially reserved for issuance pursuant to the 2010 Purchase Plan. The number of shares available for future grant under the 2010 Purchase Plan may be increased on the first day of each fiscal year by an amount equal to the lesser of: (i) 1,000,000 shares, (ii) 1% of the Class A shares of common stock outstanding on the last day of the immediately preceding fiscal year, or (iii) such lesser number of shares as is determined by the board of directors. As of December 31, 2021, there were 4,571,500 shares available for future grant under the 2010 Purchase Plan. 2010 Equity Plan The 2010 Equity Plan provided for the granting of stock options, RSAs, RSUs, and other share-based awards to employees, officers, directors, consultants, or advisors of the Company. At December 31, 2021, there were no shares available for future grant under the 2010 Equity Plan. Restricted Stock Awards RSAs are granted to non-employee members of the board of directors under restricted stock agreements in accordance with the terms of the 2019 Equity Plan and the Company’s non-employee director compensation policy, effective May 2019. Annual restricted stock grants to each non-employee member of the board of directors vest in full on the date immediately preceding the next annual meeting of stockholders, provided the individual continues to serve on the Company’s board of directors through each vest date. Initial restricted stock grants to new non-employee members of the board of directors vest annually over a three-year period from the date of grant provided the individual continues to serve on the Company’s board of directors through each vest date. A summary of restricted stock activity for the year ended December 31, 2021 is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested as of December 31, 2020 246,500 ​ $ 10.38 ​ Granted 230,160 ​ ​ 11.67 ​ Vested (213,400) ​ ​ 11.58 ​ Forfeited — ​ ​ — ​ Unvested as of December 31, 2021 263,260 ​ $ 11.61 ​ ​ The weighted-average grant date fair value per share of restricted stock awards granted during the years ended December 31, 2021, 2020, and 2019 was $11.67, $10.16, and $10.96, respectively. Amounts relating to restricted stock awards granted prior to the Separation have not been adjusted to reflect the effect of the Separation on the Company’s stock price. Restricted Stock Units RSUs granted under the Company’s equity plans represent the right to receive one share of the Company’s Class A Common Stock pursuant to the terms of the applicable award agreement. Shares of the Company’s Class A Common Stock are delivered to the employee upon vesting, subject to payment of applicable withholding taxes. Time-based RSUs Time-based RSUs generally vest over a two A summary of time-based RSU activity for the year ended December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ Average ​ ​ ​ Number ​ Grant Date ​ ​ of RSUs Fair Value Outstanding as of December 31, 2020 4,170,626 ​ $ 11.90 ​ Granted ​ 2,707,427 ​ ​ 10.40 ​ Vested and released ​ (1,697,745) ​ ​ 12.18 ​ Forfeited ​ (1,316,200) ​ ​ 11.38 ​ Outstanding as of December 31, 2021 3,864,108 ​ $ 10.89 ​ ​ The weighted-average grant date fair value per share of time-based RSUs granted during the years ended December 31, 2021, 2020, and 2019 was $10.40, $11.59, and $12.11, respectively. Amounts relating to time-based RSUs granted prior to the Separation have not been adjusted to reflect the effect of the Separation on the Company’s stock price. ​ Performance-based RSUs ​ Performance-based RSUs (“PSUs”) were granted to certain executives in 2021 and 2020. PSUs vest upon the achievement of specified performance criteria over a two ​ The fair value of Pipeline PSUs and Profitability PSUs is based on the market value of the Company's Class A Common Stock on the date of grant. The Relative TSR PSUs are valued using the Monte Carlo simulation method on the date of grant. The weighted average assumptions used to estimate the fair value of Relative TSR PSUs were as follows for the year ended December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 Fair value of common stock ​ $ 11.39 ​ Expected volatility ​ 47.9 % Expected term (in years) ​ 2.6 ​ Risk-free interest rate ​ 0.3 % Expected dividend yield ​ — % ​ ​ A summary of PSU activity for the year ended December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ Average ​ ​ ​ Number ​ Grant Date ​ ​ of PSUs Fair Value Outstanding as of December 31, 2020 586,157 ​ $ 12.48 ​ Granted ​ 661,651 ​ ​ 14.65 ​ Vested and released ​ — ​ ​ — ​ Forfeited ​ (414,522) ​ ​ 12.76 ​ Outstanding as of December 31, 2021 833,286 ​ $ 14.06 ​ ​ ​ ​ Stock Options ​ Stock options granted under the Company’s equity plans represent the right to purchase one share of the Company’s Class A Common Stock pursuant to the terms of the applicable award agreement. Shares of the Company's Class A Common Stock are delivered to the employee upon exercise, subject to payment of applicable withholding taxes. ​ As of April 2020, the Company no longer grants stock options. Stock options previously granted under the Company’s equity plans generally have a ten-year term and vest over a period of four years, provided the individual continues to serve at the Company through the vesting dates. Options granted under all equity plans are exercisable at a price per share not less than the fair market value of the underlying common stock on the date of grant. The estimated fair value of options, including the effect of estimated forfeitures, is recognized over the requisite service period, which is typically the vesting period of each option. ​ The weighted average assumptions used to estimate the fair value of the stock options using the Black-Scholes option-pricing model were as follows for the years ended December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 ​ 2019 ​ Expected volatility ​ 46.6 % 46.3 % Expected term (in years) ​ 6.1 ​ 6.1 ​ Risk-free interest rate ​ 1.5 % 2.5 % Expected dividend yield ​ — % — % ​ Expected volatility is based on the historical volatility of the Company’s Class A Common Stock. The Company estimates the expected term using historical data. The risk-free interest rate used for each grant is based on a zero-coupon U.S. Treasury instrument with a remaining term similar to the expected term of the share-based award. The Company has not paid and does not anticipate paying cash dividends on its shares of common stock in the foreseeable future; therefore, the expected dividend yield is assumed to be zero. The weighted-average grant date fair value per share of options granted during the years ended December 31, 2020 and 2019 was $5.89 and $6.10, respectively. Amounts relating to stock options granted prior to the Separation have not been adjusted to reflect the effect of the Separation on the Company’s stock price. The Company historically granted to certain employees performance-based options to purchase shares of common stock. These options are subject to performance-based milestone vesting. During the years ended December 31, 2021, 2020 and 2019, there were no shares that vested as a result of performance milestone achievements. The Company recorded an insignificant amount of share-based compensation expense related to these performance-based options during the year ended December 31, 2021 and no share-based compensation expense related to these performance-based options during the years ended December 31, 2020 and 2019. The following table summarizes stock option activity under the Company’s share-based compensation plans, including performance-based options: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Weighted- ​ ​ ​ ​ ​ Number of ​ Average ​ Average ​ Aggregate ​ ​ Stock ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Options ​ Price (1) ​ Life ​ Value ​ ​ ​ ​ ​ ​ ​ (in years) ​ (in thousands) Outstanding at December 31, 2020 13,459,671 ​ $ 12.25 ​ 4.27 ​ $ 5,613 ​ Granted — ​ ​ — ​ — ​ ​ — ​ Exercised (1,698,362) ​ ​ 10.83 ​ — ​ ​ — ​ Cancelled (2,388,515) ​ ​ 13.07 ​ — ​ ​ — ​ Outstanding at December 31, 2021 9,372,794 ​ ​ 12.30 ​ 3.51 ​ ​ 4,528 ​ Vested or expected to vest at December 31, 2021 9,331,488 ​ ​ 12.31 ​ 3.49 ​ ​ 4,509 ​ Exercisable at December 31, 2021 8,972,651 ​ ​ 12.33 ​ 3.38 ​ ​ 4,385 ​ ​ (1) Exercise prices relating to stock options granted prior to the Separation have not been adjusted to reflect the effect of the Separation on the stock options. ​ The total intrinsic value of options exercised during the years ended December 31, 2021, 2020, and 2019 was $2.7 million, $3.5 million, and $5.1 million, respectively. The intrinsic value was calculated as the difference between the fair value of the Company’s Class A Common Stock at the date of exercise and the exercise price of the option issued. The following table sets forth the Company's unrecognized share-based compensation expense, net of estimated forfeitures, as of December 31, 2021, by type of award and the weighted-average period over which that expense is expected to be recognized: ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized Weighted-Average ​ ​ Expense, Net ​ Remaining ​ ​ of Estimated ​ Recognition ​ ​ ​ Forfeitures ​ Period ​ ​ (in thousands) ​ (in years) Type of award: ​ ​ ​ ​ ​ ​ Stock options with time-based vesting ​ $ 1,541 ​ 1.14 ​ Restricted stock awards ​ ​ 1,464 ​ 0.60 ​ Time-based restricted stock units ​ ​ 22,545 ​ 2.46 ​ Performance-based restricted stock units ​ ​ 3,816 ​ 1.74 ​ Stock options with time-based and performance-based vesting ​ ​ — ​ — ​ ​ The total unrecognized share-based compensation cost will be adjusted for future changes in estimated forfeitures.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Income Taxes	14. Income Taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ — ​ $ — ​ $ — State ​ ​ 5,503 ​ ​ 2,685 ​ ​ — Total current ​ ​ 5,503 ​ ​ 2,685 ​ ​ — Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ ​ (251,367) ​ ​ — ​ ​ — State ​ ​ (81,927) ​ ​ — ​ ​ — Total deferred ​ ​ (333,294) ​ ​ — ​ ​ — Total income tax (benefit) expense ​ $ (327,791) ​ $ 2,685 ​ $ — ​ ​ During the year ended December 31, 2021, the Company recorded income tax benefit of $327.8 million, which primarily pertains to the income tax benefit of $333.3 million related to the release of the valuation allowance on the majority of the Company’s tax attributes and other deferred tax assets, partially offset by $5.5 million of state income taxes in certain states in which the Company is unable to utilize net operating losses to fully offset taxable income. During the year ended December 31, 2020, the Company recorded $2.7 million in income tax expense related to state income taxes in certain states which had temporarily disallowed or only partially allow the use of net operating losses to offset taxable income. The Company did not record a provision for federal income taxes for the period ended December 31, 2020, as it offset taxable income with federal net operating losses and recorded a full valuation allowance against net deferred tax assets. The Company did not record a provision for federal, state , or foreign income taxes for the period ended December 31, 2019 because the Company incurred a tax loss during the year and offset the benefit of these tax losses with valuation allowance. The Company has not recorded a foreign tax provision as it has had cumulative net operating losses outside of the United States since inception. On March 27, 2020. the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act was enacted and signed into law. The Company benefitted from certain provisions of the CARES Act, specifically, the increase in allowable business interest deduction from 30% of adjusted taxable income to 50% of adjusted taxable income, which allowed the Company to take additional interest deductions for the period ended December 31, 2020. Additionally, the Company was able to claim 100% bonus depreciation on leasehold improvements incurred in the period ended December 31, 2020 and 2019. A reconciliation of income taxes computed using the U.S. federal statutory rate of 21% to that reflected in the consolidated statements of income are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Income tax expense (benefit) using U.S. federal statutory rate ​ $ 42,138 ​ $ 22,861 ​ $ 4,517 ​ Permanent differences ​ 34 ​ 74 ​ 65 ​ State income taxes, net of federal benefit ​ 12,554 ​ 7,565 ​ (1,902) ​ Disallowed Separation related costs ​ ​ — ​ ​ — ​ ​ 4,658 ​ Executive compensation - Section 162(m) ​ ​ 695 ​ ​ 1,718 ​ ​ 662 ​ Meals and entertainment ​ ​ 349 ​ ​ 395 ​ ​ 495 ​ Non-deductible share-based compensation ​ 43 ​ (144) ​ (1,202) ​ Excess tax benefits ​ ​ 6,270 ​ ​ 5,132 ​ ​ 3,324 ​ Fair market valuation of Note Hedge Warrants and Convertible Note Hedges ​ ​ 325 ​ ​ 1,680 ​ ​ (290) ​ Tax credits ​ (9) ​ (3,149) ​ (4,374) ​ Expiring net operating losses and tax credits ​ 491 ​ 1,991 ​ 3,764 ​ Effect of change in state tax rate on deferred tax assets and deferred tax liabilities ​ 123 ​ (208) ​ (2,563) ​ Change in the valuation allowance ​ (390,804) ​ (35,230) ​ (7,154) ​ Income tax expense (benefit) ​ $ (327,791) ​ $ 2,685 ​ $ — ​ ​ ​ The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. These differences are measured using the enacted statutory tax rates that are expected to be in effect for the years in which differences are expected to reverse. Deferred tax assets and liabilities were determined based on the difference between financial statement and tax bases using enacted tax rates in effect for the year in which the differences are expected to reverse. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 2020 Deferred tax assets: ​ ​ ​ ​ ​ ​ ​ Net operating loss carryforwards ​ $ 165,022 ​ $ 234,772 ​ Tax credit carryforwards ​ 60,125 ​ 60,607 ​ Capitalized research and development ​ 4,981 ​ 7,498 ​ Share-based compensation ​ ​ 16,857 ​ ​ 21,848 ​ Basis difference on collaboration agreement for North America with AbbVie ​ ​ 78,194 ​ ​ 62,629 ​ Accruals and reserves ​ ​ 5,003 ​ ​ 6,114 ​ Basis difference on 2022 Convertible Notes ​ ​ 8,166 ​ ​ 6,183 ​ Intangible assets ​ ​ 5,396 ​ ​ — ​ Interest expense ​ ​ — ​ ​ 3,386 ​ Operating lease liability ​ ​ 5,971 ​ ​ 6,504 ​ Other ​ 3,997 ​ 5,049 ​ Total deferred tax assets ​ 353,712 ​ 414,590 ​ Deferred tax liabilities: ​ ​ ​ ​ ​ ​ ​ Basis difference on 2024 Convertible Notes ​ ​ (4,363) ​ ​ (5,951) ​ Basis difference on 2026 Convertible Notes ​ ​ (7,597) ​ ​ (9,022) ​ Operating lease right-of-use assets ​ ​ (4,248) ​ ​ (4,603) ​ Total deferred tax liabilities ​ ​ (16,208) ​ ​ (19,576) ​ Net deferred tax asset ​ ​ 337,504 ​ ​ 395,014 ​ Valuation allowance ​ (4,210) ​ (395,014) ​ Net deferred tax asset ​ $ 333,294 ​ $ — ​ ​ ​ On a periodic basis, the Company reassesses the valuation allowance on its deferred income tax assets weighing positive and negative evidence to assess the recoverability of the deferred tax assets. During the year ended December 31, 2021, the Company reassessed the valuation allowance noting the shift of positive evidence outweighing negative evidence, including: continued strong prescription demand growth of LINZESS, continued profitability of a GI-focused business since completing the tax-free spin-off of Cyclerion, and expectations regarding future profitability. After assessing both the positive evidence and negative evidence, management determined it was more likely than not that the Company will realize the majority of its deferred tax assets and during the year ended December 31, 2021, released the majority of its valuation allowance for the deferred tax assets that are expected to be utilized in future years. The Company will maintain a valuation allowance on deferred tax assets not expected to be realized, related primarily to certain tax credits that are expected to expire prior to utilization. The Company’s total deferred tax asset balance subject to a valuation allowance analysis was $337.5 million and $395.0 million as of December 31, 2021 and 2020, respectively. The net deferred tax assets were fully offset by a valuation allowance as of December 31, 2020. The valuation allowance decreased by $390.8 million during the year ended December 31, 2021 primarily due to the Company’s release of the majority of its valuation allowance, as described above, as well as the use of net operating losses to offset taxable income. The valuation allowance decreased $35.2 million during the year ended December 31, 2020 primarily due to the Company’s offsetting taxable income with previously disallowed interest expense and net operating losses, partially offset by an increase in deferred tax asset for the basis difference of the collaboration agreement for North America with AbbVie. Subject to the limitations described below, at December 31, 2021, the Company had federal net operating loss carryforwards of $935.4 million, of which $805.8 million is subject to expiration between 2022 and 2037 and approximately $129.6 million may be carried forward indefinitely. As of December 31, 2021, the Company had state net operating loss carryforwards of $718.9 million to offset future state taxable income, which is subject to expiration between 2022 and 2039. The Company also had tax credit carryforwards of $64.7 million as of December 31, 2021 to offset future federal and state income taxes, which is subject to expiration at various times through 2040. Utilization of net operating loss carryforwards and research and development credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that could occur in the future in accordance with Section 382 of the Internal Revenue Code of 1986 (“IRC Section 382”) and with Section 383 of the Internal Revenue Code of 1986, as well as similar state provisions. These ownership changes may limit the amount of net operating loss carryforwards and research and development credit carryforwards that can be utilized annually to offset future taxable income and taxes, respectively. In general, an ownership change, as defined by IRC Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50 percentage points over a three-year period. The following table summarizes the changes in the Company’s unrecognized income tax benefits for the years ended December 31, 2021, 2020, and 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ Balance at the beginning of the period ​ $ 68,087 ​ $ 53,099 ​ $ 38,551 ​ Increases based on tax positions related to the current period ​ ​ 83,206 ​ ​ 66,687 ​ ​ 51,699 ​ Increases for tax positions related to prior periods ​ ​ — ​ ​ — ​ ​ 1,400 ​ Decreases for tax positions in prior periods ​ ​ (66,687) ​ ​ (51,699) ​ ​ (38,551) ​ Balance at the end of the period ​ $ 84,606 ​ $ 68,087 ​ $ 53,099 ​ ​ The Company had gross unrecognized tax benefits of $84.6 million, $68.1 million, and $53.1 million as of December 31, 2021, 2020 and 2019 . total unrecognized tax benefits at December 31, 2021, $ million would, if recognized, affect the Company’s effective tax rate, and the remaining amount would not affect the Company’s effective tax rate, as it relates to a temporary timing difference. A reserve for uncertain tax positions of $ million is recorded in other liabilities on the Company’s consolidated balance sheet as of December 31, 2021. The Company will recognize interest and penalties, if any, related to uncertain tax positions in income tax expense. As of December 31, 2021, an insignificant amount of penalties have been accrued. The statute of limitations for assessment by the Internal Revenue Service (“IRS”) and state tax authorities is open for tax years ended December 31, 2018 through the present, although net operating losses generated from years prior to 2018 could be subject to examination and adjustments to the extent utilized in future years. There are currently no federal or state income tax audits in progress.

Defined Contribution Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Defined Contribution Plan	15. Defined Contribution Plan The Ironwood Pharmaceuticals, Inc. 401(k) Savings Plan is a defined contribution plan in the form of a qualified 401(k) plan in which substantially all employees are eligible to participate upon employment. Subject to certain IRS limits, eligible employees may elect to contribute from 1% to 100% of their compensation. Company contributions to the plan are at the sole discretion of the Company. During the year ended December 31, 2021, the Company provided a matching contribution equal to the greater of: (a) 100% of employee contributions on the first 3% of eligible compensation and 50% of employee contributions on the next 3% of eligible compensation; or (b) 75% of the first $10,000 of employee contributions, up to $7,500. During the years ended December 31, 2020 and 2019, the Company provided a matching contribution of 75% of the employee’s contributions, up to $6,000 annually. During the years ended December 31, 2021, 2020, and 2019, the Company recorded $2.2 million, $1.8 million, and $2.2 million of expense related to its 401(k) company match, respectively.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Related Party Transactions	16. Related Party Transactions The Company previously reflected amounts due from and due to Allergan plc prior to its acquisition by AbbVie in May 2020 as related party receivables and payables, as appropriate. Following the acquisition of Allergan plc by AbbVie, the Company determined that AbbVie is not a related party to the Company. ​ In connection with the Separation, the Company executed certain contracts with Cyclerion, whose President and Chief Scientific Officer at the time of the Separation became a member of the Company’s Board of Directors in April 2019 (Note 3). As of December 31, 2020, the Company determined that Cyclerion was no longer considered a related party. ​

Workforce Reduction and Restruc

Workforce Reduction and Restructuring	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Workforce Reduction and Restructuring	17. Workforce Reductions and Restructuring During the years ended December 31, 2021, 2020, and 2019 the Company recorded an insignificant amount, $15.4 million, and $3.6 million in restructuring expenses, respectively, in its consolidated statements of income. ​ In August 2018, the Company initiated a reduction in its workforce by approximately 100 employees, primarily consisting of field-based sales representatives in connection with the termination of the lesinurad license agreement and substantially completed the reduction in its workforce and recorded associated costs during the year ended December 31, 2018. During the years ended December 31, 2020 and 2019, the Company recorded an insignificant amount of adjustments to restructuring costs related to this workforce reduction. ​ In February 2019, following further analysis of the Company’s strategy and core business needs, and in an effort to further strengthen the operational efficiency of the organization, the Company commenced a reduction in workforce by approximately 35 employees, primarily based in the home office and substantially completed the reduction in its workforce and recorded associated costs during the year ended December 31, 2019. During the year ended December 31, 2019, the Company recorded $3.7 million of severance, benefits and related costs as restructuring expenses related to this reduction in workforce. ​ In September 2020, the Company announced that one of its two identical Phase III trials evaluating IW-3718 in refractory GERD did not meet certain criteria, including the study’s primary endpoint of achieving a statistically significant improvement in heartburn severity. Based on these findings, the Company discontinued development of IW-3718. In connection with this decision, the Company reduced its workforce by approximately 100 full-time employees. This workforce reduction affected both field-based and home-office employees, including the relevant general and administrative support functions. The Company substantially completed the reduction in its workforce in the year ended December 31, 2020. The Company incurred an insignificant amount and $15.5 million during the years ended December 31, 2021 and 2020, respectively, in restructuring expenses, primarily for severance, benefits and related costs related to this reduction in its workforce. Restructuring expenses during the year ended December 31, 2020 also included $1.2 million related to the impairment of certain fixed assets as a result of the Company’s decision to discontinue IW-3718 development. ​ The following table summarizes the accrued liabilities activity recorded in connection with the reduction in workforce in September 2020 and related restructuring activities during the year ended December 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ Accrued at ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued at ​ December 31, 2020 Charges ​ Amount Paid ​ Adjustments ​ December 31, 2021 Employee severance, benefits and related costs ​ $ 10,902 ​ $ 1,025 ​ $ (10,611) ​ $ (854) ​ $ 462 Contract related costs ​ ​ 5 ​ ​ 48 ​ ​ (53) ​ ​ — ​ ​ — Total $ 10,907 ​ $ 1,073 ​ $ (10,664) ​ $ (854) ​ $ 462 ​ The following table summarizes the accrued liabilities activity recorded in connection with the reductions in workforce and related restructuring activities during the year ended December 31, 2020 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ Accrued at ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued at ​ December 31, 2019 Charges ​ Amount Paid ​ Adjustments ​ December 31, 2020 Employee severance, benefits and related costs ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ February 2019 Reduction $ 75 ​ $ — ​ $ (75) ​ $ — ​ $ — September 2020 Reduction ​ ​ — ​ ​ 11,563 ​ ​ (661) ​ ​ — ​ ​ 10,902 Total $ 75 ​ $ 11,563 ​ $ (736) ​ $ — ​ $ 10,902 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract related costs ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ August 2018 Reduction ​ $ 104 ​ $ — ​ $ — ​ $ (104) ​ $ — September 2020 Reduction ​ ​ — ​ ​ 108 ​ ​ (103) ​ ​ — ​ ​ 5 Total $ 104 ​ $ 108 ​ $ (103) ​ $ (104) ​ $ 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2018
Disclosure Text Block
Selected Quarterly Financial Data (Unaudited)	18. Selected Quarterly Financial Data (Unaudited) The following table contains quarterly financial information for the years ended December 31, 2021 and 2020. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair presentation of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First ​ Second ​ Third ​ Fourth ​ Total ​ ​ Quarter ​ Quarter ​ Quarter ​ Quarter ​ Year ​ ​ (in thousands, except per share data) 2021 ​ ​ ​ ​ ​ Total revenues ​ $ 88,845 ​ $ 104,031 ​ $ 103,747 ​ $ 117,130 ​ $ 413,753 ​ Total cost and expenses ​ 43,447 ​ 38,933 ​ ​ 38,576 ​ ​ 60,538 ​ 181,494 ​ Other expense, net ​ (5,040) ​ (10,726) ​ ​ (5,499) ​ ​ (10,337) ​ (31,602) ​ Net income and comprehensive income ​ 39,926 ​ 391,303 ​ ​ 55,845 ​ ​ 41,374 ​ 528,448 ​ Net income per share—basic ​ ​ 0.25 ​ ​ 2.42 ​ ​ 0.34 ​ ​ 0.25 ​ ​ 3.26 ​ Net income per share—diluted ​ ​ 0.25 ​ ​ 2.39 ​ ​ 0.34 ​ ​ 0.25 ​ ​ 3.21 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First ​ Second ​ Third ​ Fourth ​ Total ​ ​ Quarter ​ Quarter ​ Quarter ​ Quarter ​ Year ​ ​ (in thousands, except per share data) 2020 ​ ​ ​ ​ ​ Total revenues ​ $ 79,943 ​ $ 89,432 ​ $ 103,468 ​ $ 116,680 ​ $ 389,523 ​ Total cost and expenses ​ 66,716 ​ 56,719 ​ 57,852 ​ 65,296 ​ 246,583 ​ Other expense, net ​ (9,882) ​ (7,509) ​ (9,804) ​ (6,884) ​ (34,079) ​ Net income and comprehensive income ​ 3,345 ​ 25,204 ​ 34,423 ​ 43,204 ​ 106,176 ​ Net income per share—basic ​ ​ 0.02 ​ ​ 0.16 ​ ​ 0.22 ​ ​ 0.27 ​ ​ 0.67 ​ Net income per share—diluted ​ ​ 0.02 ​ ​ 0.16 ​ ​ 0.21 ​ ​ 0.27 ​ ​ 0.66 ​ ​

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block
Subsequent Events	19. Subsequent Events ​ Share Repurchases ​ From January 1, 2022 to February 15, 2022, the Company repurchased 4.5 million shares of its common stock at a weighted-average price of $11.27 per share for a total of $50.7 million. ​ ​ ​ ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Policy Text Blocks
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Ironwood and its wholly-owned subsidiaries, as of December 31, 2021, Ironwood Pharmaceuticals Securities Corporation and Ironwood Pharmaceuticals GmbH. Cyclerion Therapeutics, Inc. (“Cyclerion”) was a wholly-owned subsidiary until it became an independent publicly-traded company on April 1, 2019 (Note 3). All intercompany transactions and balances are eliminated in consolidation.
Segment Information	Segment Information Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Company’s chief operating decision-maker in deciding how to allocate resources and in assessing performance. The Company currently operates in one reportable business segment—human therapeutics.
Reclassifications	Reclassifications Certain prior period financial statement items have been reclassified to conform to current period presentation.
Discontinued Operations	Discontinued Operations ​ The Company determined that its soluble guanylate cyclase (“sGC”) business, which was disposed on April 1, 2019, met the criteria for classification as a discontinued operation in accordance with Accounting Standards Codification (“ASC”) Subtopic 205-20, Discontinued Operations Cyclerion Separation
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in accordance with U.S. generally accepted accounting principles requires the Company’s management to make estimates and judgments that may affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of revenues and expenses during the reported periods. On an ongoing basis, the Company’s management evaluates its estimates, judgments and methodologies. Significant estimates and assumptions in the consolidated financial statements include those related to revenue recognition; accounts receivable; useful lives of long-lived assets, impairment of long-lived assets, including goodwill; valuation procedures for right-of-use assets and operating lease liabilities; valuation procedures for the issuance and repurchase of convertible notes; balance sheet classification of convertible notes; fair value of derivatives; income taxes, including the valuation allowance for deferred tax assets; research and development expenses; contingencies and share-based compensation. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ materially from these estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investment instruments with a remaining maturity when purchased of three months or less to be cash equivalents. Investments qualifying as cash equivalents primarily consist of money market funds, U.S. government-sponsored securities, and repurchase agreements. The carrying amount of cash equivalents approximates fair value. The amount of cash equivalents included in cash and cash equivalents was $595.2 million and $349.0 million at December 31, 2021 and 2020, respectively.
Restricted Cash	Restricted Cash The Company is contingently liable under unused letters of credit with a bank, related to the Company’s facility lease and vehicle lease agreements, in the amount of $1.7 million and $2.2 million as of December 31, 2021 and 2020, respectively. The Company records as restricted cash the collateral used to secure these letters of credit. The amount of restricted cash included in current assets and non-current assets was $1.3 million and $0.5 million, respectively, at December 31, 2021. The amount of restricted cash in current assets and non-current assets was $1.7 million and $0.5 million, respectively, at December 31, 2020.
Concentrations of Suppliers	Concentrations of Suppliers The Company relies on its collaboration partners and their suppliers to manufacture linaclotide API, linaclotide finished drug product, and finished goods. If any of the Company’s collaboration partners and their suppliers were to limit or terminate production or otherwise fail to meet the quality or delivery requirements needed to satisfy the supply commitments, the process of locating and qualifying alternate sources could require up to several months, during which time production could be delayed. Such delays could have a material adverse effect on the Company’s business, financial position and results of operations.
Accounts Receivable and Related Valuation Account	Accounts Receivable and Related Valuation Account The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for credit losses when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices and the overall quality and age of those invoices not specifically reviewed. The Company’s receivables relate primarily to amounts reimbursed under its collaboration, license and co-promotion agreements. The Company believes that credit risks associated with these partners are not significant. The Company reviews the need for an allowance for credit losses for its receivables based on various factors including payment history and historical bad debt experience. The Company had no allowance for credit losses as of December 31, 2021 or 2020.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents, restricted cash, and accounts receivable. The Company maintains its cash and cash equivalent balances with high-quality financial institutions and the Company believes that such funds are subject to minimal credit risk. The Company has adopted an investment policy which limits the amounts the Company may invest in certain types of investments, and requires all investments held by the Company to be at least AA- rated, thereby reducing credit risk exposure. Accounts receivable primarily consist of amounts due under the linaclotide collaboration agreement with AbbVie for North America (Note 5). The Company does not obtain collateral for its accounts receivable. The Company previously reflected amounts due from Allergan, net of amounts payable to Allergan, prior to its acquisition by AbbVie as related party accounts receivable, net. Following the acquisition of Allergan by AbbVie, the Company determined that AbbVie is not a related party to the Company (Note 16). The percentages of revenue recognized from significant collaborative partners of the Company in the years ended December 31, 2021, 2020 and 2019 as well as the account receivable balances, net of any payables due, at December 31, 2021 and 2020 are included in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts Receivable ​ Revenue ​ ​ December 31, ​ Year Ended December 31, ​ 2021 2020 2021 2020 2019 Collaborative Partner: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ AbbVie (North America and Europe) 81 % 76 % 98 % 96 % 78 % Astellas (Japan) 1 % 1 % 1 % 1 % 13 % ​
Property and Equipment	Property and Equipment ​ Property and equipment, including leasehold improvements, are recorded at cost, and are depreciated when placed into service using the straight-line method based on their estimated useful lives as follows: ​ ​ ​ ​ ​ ​ Estimated Useful Life Asset Description (In Years) Laboratory equipment 5 ​ Computer and office equipment 3 ​ Furniture and fixtures 7 ​ Software 3 ​ ​ Included in property and equipment are certain costs of software obtained for internal use. Costs incurred during the preliminary project stage are expensed as incurred, while costs incurred during the application development stage are capitalized and amortized over the estimated useful life of the software. The Company also capitalizes costs related to specific upgrades and enhancements when it is probable the expenditures will result in additional functionality. Maintenance and training costs related to software obtained for internal use are expensed as incurred. Leasehold improvements are amortized over the shorter of the estimated useful life of the asset or the lease term. Costs for capital assets not yet placed into service have been capitalized as construction in process, and will be depreciated in accordance with the above guidelines once placed into service. Maintenance and repair costs are expensed as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company regularly reviews the carrying amount of its long-lived assets to determine whether indicators of impairment may exist, which warrant adjustments to carrying values or estimated useful lives. If indications of impairment exist, projected future undiscounted cash flows associated with the asset are compared to the carrying amount to determine whether the asset’s value is recoverable. If the carrying value of the asset exceeds such projected undiscounted cash flows, the asset will be written down to its estimated fair value.
Income Taxes	Income Taxes The Company provides for income taxes under the asset and liability method. Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates in effect when the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance to reflect the uncertainty associated with their ultimate realization. The Company accounts for uncertain tax positions recognized in the consolidated financial statements in accordance with the provisions of ASC Topic 740, Income Taxes
Financing Costs	Financing Costs Financing costs include costs directly attributable to the Company’s offerings of its equity securities and its debt financings. Costs attributable to equity offerings are charged as a reduction to stockholders’ equity against the proceeds of the offering once the offering is completed. Costs attributable to debt financings are deferred and amortized to interest expense over the term of the debt using the effective interest method. Costs incurred in connection with convertible debt securities are allocated between the liability and equity components. In accordance with ASC 835, Interest
Leases	Leases Effective January 1, 2019, the Company adopted ASC Topic 842, Leases optional transition method ​ As part of the ASC 842 adoption, the Company elected certain practical expedients, which include: ​ ● Accounting policy election to use the short-term lease exception by asset class; and ● Election of the practical expedient package during transition, which includes: o An entity need not reassess whether any expired or existing contracts are or contain leases. o An entity need not reassess the classification for any expired or existing leases. As a result, all leases that were classified as operating leases in accordance with ASC 840 are classified as operating leases under ASC 842, and all leases that were classified as capital leases in accordance with ASC 840 are classified as finance leases under ASC 842. o An entity need not reassess initial direct costs for any existing leases. ​ Subsequent to the Company’s adoption of ASC 842, the Company elected the post-transition practical expedient, by class of underlying asset, to account for lease components and non-lease components together as a single component for the asset class of operating lease right-of-use real estate assets. ​ The Company’s lease portfolio for the year ended December 31, 2021 included: a lease for its headquarters location, a data center colocation lease, vehicle leases for its salesforce representatives, and leases for computer and office equipment. The Company determines if an arrangement is a lease at the inception of the contract. The asset component of the Company’s operating leases is recorded as operating lease right-of-use assets, and the liability component is recorded as current portion of operating lease liabilities and operating lease liabilities, net of current portion in the Company’s consolidated balance sheets. As of December 31, 2021, the Company did not record any finance leases. ​ Right-of-use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at the lease inception date. Existing leases in the Company’s lease portfolio as of the adoption date were valued as of January 1, 2019. The Company uses an incremental borrowing rate based on the information available at lease inception in determining the present value of lease payments, if an implicit rate of return is not provided with the lease contract. Operating lease right-of-use assets are adjusted for incentives expected to be received. ​ Right-of-use assets and operating lease liabilities are remeasured upon certain modifications to leases using the present value of remaining lease payments and estimated incremental borrowing rate upon lease modification. ​ Lease cost is recognized on a straight-line basis over the lease term, and includes amounts related to short-term leases. The Company recognizes variable lease payments as operating expenses in the period in which the obligation for those payments is incurred. Variable lease payments primarily include common area maintenance, utilities, real estate taxes, insurance, and other operating costs that are passed on from the lessor in proportion to the space leased by the Company.
Derivative Assets and Liabilities	Derivative Assets and Liabilities In June 2015, the Company issued Convertible Senior Notes due 2026 (the “2026 Convertible Notes”, and together with the 2022 Convertible Notes and the 2024 Convertible Notes, the “Convertible Senior Notes”). I Derivatives and Hedging ​ These derivatives are recorded as assets or liabilities at fair value each reporting date and the fair value is determined using the Black-Scholes option-pricing model. The changes in fair value are recorded as a component of other (expense) income in the consolidated statements of income. Significant inputs used to determine the fair value as of December 31, 2021 included the price per share of the Company’s Class A Common Stock, expected terms of the derivative instruments, strike prices of the derivative instruments, risk-free interest rates, and expected volatility of the Company’s Class A Common Stock. Changes to these inputs could materially affect the valuation of the Convertible Note Hedges and Note Hedge Warrants. In August 2019, in connection with the issuance of the 2024 Convertible Notes and the 2026 Convertible Notes, the Company entered into the Capped Calls. The Capped Calls cover the same number of shares of Class A Common Stock that initially underlie the 2024 Convertible Notes and the 2026 Convertible Notes (subject to anti-dilution and certain other adjustments). These instruments meet the conditions outlined in ASC 815 to be classified in stockholders’ equity (deficit) and are not subsequently remeasured as long as the conditions for equity classification continue to be met.
Share Repurchases	Share Repurchases ​ The Company accounts for repurchases of its Class A Common Stock on the trade date by recording the excess of the repurchase price over the par value entirely to additional paid-in capital. All repurchased shares are retired or constructively retired. Issued and outstanding shares are reduced by shares repurchased.
Revenue Recognition	Revenue Recognition The Company’s revenues are generated primarily through collaborative arrangements and license agreements related to the research and development and commercialization of linaclotide, as well as co-promotion arrangements in the U.S. The terms of the collaborative research and development, license, co-promotion and other agreements contain multiple performance obligations which may include (i) licenses, (ii) research and development activities, including participation on joint steering committees, (iii) the manufacture of finished drug product, API, or development materials for a partner, which are reimbursed at a contractually determined rate, and (iv) education or co-promotion activities by the Company’s clinical sales specialists. Non-refundable payments to the Company under these agreements may include (i) up-front license fees, (ii) payments for research and development activities, (iii) payments for the manufacture of finished drug product, API, or development materials, (iv) payments based upon the achievement of certain milestones, (v) payments for sales detailing, promotional support services and medical education initiatives, and (vi) royalties on product sales. The Company receives its share of the net profits or bears its share of the net losses from the sale of linaclotide in the U.S. through its collaboration agreement with AbbVie for North America. The Company has adopted a policy to recognize revenue net of tax withholdings, as applicable. Collaboration, License, Co-Promotion and Other Commercial Agreements Upon licensing intellectual property to a customer, the Company determines if the license is distinct from the other performance obligations identified in the arrangement. The Company recognizes revenues from the transaction price, including non-refundable, up-front fees allocated to the license when the license is transferred to the customer if the license has distinct benefit to the customer. For licenses that are combined with other promises, the Company assesses the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. For performance obligations that are satisfied over time, the Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company’s license and collaboration agreements include milestone payments, such as development and other milestones. The Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method at the inception of the agreement. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative standalone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. The Company re-evaluates the probability of achievement of such milestones and any related constraint at each reporting period, and any adjustments are recorded on a cumulative catch-up basis. Agreements that include the supply of API or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered as options. The Company assesses if these options provide a material right to its partner, and if so, they are accounted for as separate performance obligations. If the Company is entitled to additional payments when the customer exercises these options, any additional payments are recorded as revenue when the customer obtains control of the goods, which is typically upon shipment for sales of API and finished drug product. For agreements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue when the related sales occur. Net Profit or Net Loss Sharing In accordance with ASC 808 Topic, Collaborative Arrangements Revenue from Contracts with Customers The Company’s collaborative arrangements revenues generated from sales of LINZESS in the U.S. are considered akin to sales-based royalties. In accordance with the sales-based royalty exception, the Company recognizes its share of the pre-tax commercial net profit or net loss generated from the sales of LINZESS in the U.S. in the period the product sales are earned, as reported by AbbVie, and related cost of goods sold and selling, general and administrative expenses as incurred by the Company and AbbVie. These amounts are partially determined based on amounts provided by AbbVie and involve the use of estimates and judgments, such as product sales allowances and accruals related to prompt payment discounts, chargebacks, governmental and contractual rebates, wholesaler fees, product returns, and co-payment assistance costs, which could be adjusted based on actual results in the future. The Company is highly dependent on AbbVie for timely and accurate information regarding net revenues from sales of LINZESS in the U.S. in accordance with both ASC 808 and ASC 606, and the related costs, in order to accurately report its results of operations. If the Company does not receive timely and accurate information or incorrectly estimates activity levels associated with the collaboration at a given point in time, the Company could be required to record adjustments in future periods. In accordance with ASC 606-10-55, Principal Agent Considerations Sale of Active Pharmaceutical Ingredient During the years ended December 31, 2020, and 2019, the Company produced linaclotide API, finished drug product, finished goods, and/or development materials for certain of its partners. As of December 31, 2020, the Company was no longer responsible for the supply of linaclotide API, finished drug product, finished goods or development materials to its partners, though the Company may provide development materials to certain of our partners on a periodic basis. Sales of such development materials have been and are expected to continue to be immaterial. The Company recognizes revenue on linaclotide API, finished drug product, finished goods, and development materials when control has transferred to the partner, which generally occurs upon shipment after the material passed all quality testing required for acceptance by the partner. Prior to the execution of the Amended AstraZeneca Agreement in September 2019, any linaclotide API, finished drug product, and development materials produced for AstraZeneca for China (including Hong Kong and Macau) were recognized in accordance with the cost-sharing provisions of the AstraZeneca collaboration agreement. Other The Company’s deferred revenue balance consists of advance billings and payments received from customers in excess of revenue recognized.
Cost of Revenues	Cost of Revenues Cost of revenues includes cost related to the sales of linaclotide API, finished drug product, and finished goods and are generally recognized upon shipment to certain of the Company’s partners outside of the U.S. The Company’s cost of revenues for linaclotide consists of the internal and external costs of producing such API, finished drug product, and finished goods.
Research and Development Costs	Research and Development Costs The Company generally expenses research and development costs to operations as incurred. The Company capitalizes nonrefundable advance payments made by the Company for research and development activities and defers expense recognition until the related goods are received or the related services are performed. Research and development expenses are comprised of costs incurred in performing research and development activities, including salary, benefits, share-based compensation, and other employee-related expenses; laboratory supplies and other direct expenses; facilities expenses; overhead expenses; third-party contractual costs relating to nonclinical studies and clinical trial activities and related contract manufacturing expenses, development of manufacturing processes and regulatory registration of third-party manufacturing facilities; licensing fees for the Company’s product candidates; and other outside expenses. The Company has certain collaboration agreements pursuant to which it shares or has shared research and development expenses related to linaclotide. The Company records expenses incurred under such linaclotide collaboration arrangements as research and development expense. Prior to the execution of the Amended AstraZeneca Agreement in September 2019, under the Company’s collaboration agreement with AstraZeneca for China (including Hong Kong and Macau), the Company was reimbursed for certain research and development expenses and it netted these reimbursements against its research and development expenses as incurred. In connection with the execution of the Amended AstraZeneca Agreement, AstraZeneca is fully responsible for all research and development costs incurred related to the development, manufacture, and commercialization of linaclotide in China (including Hong Kong and Macau). Under the Company’s collaboration agreement with AbbVie for North America, the Company is reimbursed for certain research and development expenses and nets these reimbursements against its research and development expenses as incurred. ​ Research and development expense includes up-front payment, non-contingent payment, and milestone payment obligations under the COUR Collaboration Agreement (Note 5). Expense is recognized when the obligation is determined to be probable.
Restructuring Expenses	Restructuring Expenses Restructuring expenses are comprised primarily of costs associated with exit and disposal activities in accordance with ASC 420, Exit or Disposal Cost Obligations
Selling, General and Administrative Expenses	Selling, General and Administrative Expenses The Company expenses selling, general and administrative costs to operations as incurred. Selling, general and administrative expenses consist primarily of compensation, benefits and other employee-related expenses for personnel in the Company’s administrative, finance, legal, information technology, business development, commercial, sales, marketing, communications and human resources functions. Other costs include the legal costs of pursuing patent protection of the Company’s intellectual property, general and administrative related facility costs, insurance costs and professional fees for accounting, tax, consulting, legal and other services. Prior to the execution of the Amended AstraZeneca Agreement, the Company was reimbursed for certain selling, general and administrative expenses and the Company netted these reimbursements against the Company’s selling, general and administrative expenses as incurred. In connection with the Amended AstraZeneca Agreement, effective in September 2019, AstraZeneca is fully responsible for all costs related to the development, manufacture, and commercialization of linaclotide in China (including Hong Kong and Macau). The Company includes AbbVie’s selling, general and administrative cost-sharing payments in the calculation of the net profits and net losses from the sale of LINZESS in the U.S. and presents the net payment to or from AbbVie as collaboration expense or collaborative arrangements revenue, respectively.
Share-Based Compensation Expense	Share-Based Compensation Expense The Company grants awards under its share-based compensation programs, including stock awards, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) (including both time-based and performance-based RSUs), stock options, and shares issued under the Company’s employee stock purchase plan (“ESPP”). Share-based compensation is recognized as expense in the consolidated statements of income based on the grant date fair value over the requisite service period, net of estimated forfeitures. The Company estimates forfeitures over the requisite service period using historical forfeiture activity and records share-based compensation expense only for those awards that are expected to vest. The Company estimates the fair value of stock options using the Black-Scholes option-pricing model, which requires the use of subjective assumptions including volatility and expected term, among others. The fair value of stock awards, RSAs, and RSUs is based on the market value of the Company’s Class A Common Stock on the date of grant, with the exception of performance-based RSUs with market conditions, which are measured using the Monte Carlo simulation method on the date of grant (Note 13). Discounted stock purchases under the Company’s ESPP are valued on the first date of the offering period using the Black-Scholes option-pricing model to compute the fair value of the lookback provision plus the purchase discount. For awards that vest based on service conditions and market conditions, the Company uses a straight-line method to recognize compensation expense over the respective service period. For awards that contain performance conditions, the Company determines the appropriate amount to expense at each reporting date based on the anticipated achievement of performance targets, which requires judgement, including forecasting the achievement of future specified targets. At the date performance conditions are determined to be probable of achievement, the Company records a cumulative expense catch-up, with remaining expense amortized over the remaining service period. Throughout the performance period, the Company re-assesses the estimated performance and updates the number of performance-based awards that it believes will ultimately vest. Discounted stock purchases under the Company’s ESPP are recognized over the offering period. Compensation expense related to modified awards is measured based on the fair value for the awards as of the modification date. Any incremental compensation expense arising from the excess of the fair value of the awards on the modification date compared to the fair value of the awards immediately before the modification date is recognized at the modification date or ratably over the requisite remaining service period, as appropriate. While the assumptions used to calculate and account for share-based compensation awards represent management’s best estimates, these estimates involve inherent uncertainties and the application of management’s judgment. As a result, if revisions are made to the Company’s underlying assumptions and estimates, the Company’s share-based compensation expense could vary significantly from period to period.
Patent Costs	Patent Costs The Company incurred and recorded as operating expense legal and other fees related to patents of $1.7 million, $2.3 million, and $7.8 million for the years ended December 31, 2021, 2020 and 2019, respectively. These costs were charged to selling, general and administrative expenses as incurred.
Net Income Per Share	Net Income Per Share Basic net income per common share is computed by dividing the net income by the weighted average number of common shares outstanding during the period. Diluted net income per common share is computed by dividing net income by the diluted number of shares outstanding during the period. Except where the result would be antidilutive to net income, diluted net income per common share is computed assuming the conversion of the 2022 Convertible Notes, the 2024 Convertible Notes and the 2026 Convertible Notes, the exercise of outstanding common stock options and the vesting of RSUs and RSAs (using the treasury stock method), as well as their related income tax effects.
Subsequent Events	Subsequent Events The Company considers events or transactions that have occurred after the balance sheet date of December 31, 2021, but prior to the filing of the financial statements with the Securities and Exchange Commission (“SEC”) to provide additional evidence relative to certain estimates or to identify matters that require additional recognition or disclosure. Subsequent events have been evaluated through the filing of the financial statements accompanying this Annual Report on Form 10-K.
New Accounting Pronouncements	New Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (the “FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Except as set forth below, the Company did not adopt any new accounting pronouncements during the year ended December 31, 2021 that had a material effect on its consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , March 31 , 2021 ​ In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging— Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity In May 2021, the FASB issued ASU No. 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options Other recent accounting pronouncements issued, but not yet effective, are not expected to be applicable to the Company or have a material effect on the consolidated financial statements upon future adoption.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
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Schedule of percentages of revenue and accounts receivable recognized from significant customers	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts Receivable ​ Revenue ​ ​ December 31, ​ Year Ended December 31, ​ 2021 2020 2021 2020 2019 Collaborative Partner: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ AbbVie (North America and Europe) 81 % 76 % 98 % 96 % 78 % Astellas (Japan) 1 % 1 % 1 % 1 % 13 %
Schedule of property and equipment	​ ​ ​ ​ ​ ​ Estimated Useful Life Asset Description (In Years) Laboratory equipment 5 ​ Computer and office equipment 3 ​ Furniture and fixtures 7 ​ Software 3 ​ ​ Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 2020 Software ​ $ 5,667 ​ $ 8,615 ​ Leasehold improvements ​ 7,407 ​ 7,407 ​ Laboratory equipment ​ 1,327 ​ 1,898 ​ Furniture and fixtures ​ 1,517 ​ 1,517 ​ Computer and office equipment ​ 1,285 ​ 1,297 ​ Total property and equipment ​ 17,203 ​ 20,734 ​ Less accumulated depreciation and amortization ​ (9,628) ​ (11,805) ​ Total property and equipment, net ​ $ 7,575 ​ $ 8,929 ​

Cyclerion Separation (Tables)

Cyclerion Separation (Tables)	12 Months Ended
	Dec. 31, 2021
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Summary of assets and liabilities transferred in separation	​ ​ ​ ​ ​ ​ ​ As of April 1, 2019 ​ Assets: ​ ​ ​ ​ Prepaid expenses and other current assets ​ $ 1,169 ​ Property and equipment, net ​ ​ 10,241 ​ Other assets ​ ​ 21 ​ ​ ​ $ 11,431 ​ Liabilities: ​ ​ ​ ​ Accrued research and development costs ​ $ 5,673 ​ Accrued expenses and other current liabilities ​ ​ 3,149 ​ ​ ​ $ 8,822 ​ Net Assets Transferred to Cyclerion ​ $ 2,609 ​
Summary of the discontinued operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2019 Costs and expenses: ​ ​ ​ ​ Research and development ​ $ 21,792 ​ Selling, general and administrative ​ 15,646 ​ Net loss from discontinued operations ​ $ 37,438 ​

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
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Schedule of computation of basic and diluted net loss per common share	The following table sets forth the computation of basic and diluted net income per common share (in thousands, except per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 ​ 2020 2019 Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 528,448 ​ $ 106,176 ​ $ 21,505 Denominator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — basic ​ 162,245 ​ 159,427 ​ 156,023 Effect of dilutive securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options ​ ​ 488 ​ ​ 367 ​ ​ — Time-based restricted stock units ​ ​ 1,422 ​ ​ 766 ​ ​ — Performance-based restricted stock units ​ ​ 146 ​ ​ 1 ​ ​ — Restricted stock ​ ​ 117 ​ ​ 94 ​ ​ — Dilutive potential common shares ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — diluted ​ ​ 164,418 ​ 160,655 ​ ​ 156,023 Net income per share — basic ​ ​ 3.26 ​ 0.67 ​ ​ 0.14 Net income per share — diluted ​ $ 3.21 ​ $ 0.66 ​ $ 0.14
Schedule of potentially dilutive securities that have been excluded from computation of diluted weighted average shares outstanding	The outstanding securities have been excluded from the computation of diluted weighted average shares outstanding, as applicable, as their effect would be anti-dilutive (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Stock options 7,701 11,746 17,194 ​ Restricted stock awards — 2 182 ​ Time-based restricted stock units ​ 102 ​ 209 ​ 3,207 ​ Performance-based restricted stock units ​ 121 ​ 93 ​ — ​ Note Hedge Warrants ​ 8,318 ​ 8,318 ​ 8,318 ​ 2022 Convertible Notes ​ 8,318 ​ 8,318 ​ 8,318 ​ 2024 Convertible Notes ​ 14,934 ​ 14,934 ​ 14,934 ​ 2026 Convertible Notes ​ 14,934 ​ 14,934 ​ 14,934 ​ Total 54,428 58,554 67,087 ​

Collaboration, License, and O_2

Collaboration, License, and Other Agreements (Tables)	12 Months Ended
	Dec. 31, 2021
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Schedule of revenue attributable to transactions from collaboration and license arrangements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Collaborative Arrangements Revenue 2021 2020 2019 Linaclotide Collaboration and License Agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ AbbVie (North America) ​ $ 403,085 $ 370,902 $ 327,591 ​ AbbVie (Europe and other) ​ ​ 2,558 ​ ​ 2,196 ​ ​ 1,718 ​ AstraZeneca (China, including Hong Kong and Macau) ​ ​ 743 ​ 682 ​ 32,628 ​ Astellas (Japan) ​ ​ 2,232 ​ 2,128 ​ 10,147 ​ Co-Promotion and Other Agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ AbbVie (VIBERZI) (1) ​ ​ — ​ ​ — ​ ​ 3,723 ​ Alnylam (GIVLAARI) ​ ​ 2,411 ​ ​ 4,302 ​ ​ 2,000 ​ Other ​ ​ 1,755 ​ ​ 1,335 ​ ​ 1,845 ​ Total collaborative arrangements revenue ​ $ 412,784 ​ $ 381,545 ​ $ 379,652 ​ Sale of API ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Linaclotide Agreements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Astellas (Japan) ​ $ 149 ​ $ 2,017 ​ $ 45,788 ​ AstraZeneca (China, including Hong Kong and Macau) ​ ​ 597 ​ ​ 5,540 ​ ​ 2,973 ​ Other ​ ​ 223 ​ ​ 421 ​ ​ — ​ Total sale of API ​ $ 969 ​ $ 7,978 ​ $ 48,761 ​ (1) The Company had an agreement with AbbVie to perform sales detailing activities for VIBERZI® (eluxadoline) which terminated as of December 31, 2019. ​
AbbVie
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Schedule of revenue attributable to transactions from collaboration and license arrangements	The Company recognized collaborative arrangements revenue from the AbbVie collaboration agreement for North America during the years ended December 31, 2021, 2020, and 2019 as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Collaborative arrangements revenue related to sales of LINZESS in the U.S. ​ $ 400,371 ​ $ 368,603 ​ $ 325,429 ​ Royalty revenue ​ 2,714 ​ 2,299 ​ 2,162 ​ Total collaborative arrangements revenue ​ $ 403,085 ​ $ 370,902 ​ $ 327,591 ​
Schedule of amount recorded by the Company for share of net loss related to collaborative arrangement	​

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
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Schedule of assets and liabilities measured at fair value on a recurring basis	The following tables present the assets and liabilities the Company has measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting Date Using ​ ​ ​ Quoted Prices in Significant Other Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ December 31, ​ Identical Assets ​ Inputs ​ Inputs ​ ​ 2021 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 595,233 ​ $ 595,233 ​ $ — ​ $ — Restricted cash: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 1,735 ​ ​ 1,735 ​ ​ — ​ ​ — Convertible note hedges ​ ​ 1,115 ​ ​ — ​ ​ — ​ ​ 1,115 Total assets measured at fair value ​ $ 598,083 ​ $ 596,968 ​ $ — ​ $ 1,115 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Note hedge warrants ​ $ 1,316 ​ $ — ​ $ — ​ $ 1,316 Total liabilities measured at fair value ​ $ 1,316 ​ $ — ​ $ — ​ $ 1,316 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting Date Using ​ ​ ​ Quoted Prices in Significant Other Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ December 31, ​ Identical Assets ​ Inputs ​ Inputs ​ ​ 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 349,014 ​ $ 349,014 ​ $ — ​ $ — Restricted cash: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ 2,221 ​ 2,221 ​ — ​ — Convertible note hedges ​ ​ 13,065 ​ ​ — ​ ​ — ​ ​ 13,065 Total assets measured at fair value ​ $ 364,300 ​ $ 351,235 ​ $ — ​ $ 13,065 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Note hedge warrants ​ $ 12,088 ​ $ — ​ $ — ​ $ 12,088 Total liabilities measured at fair value ​ $ 12,088 ​ $ — ​ $ — ​ $ 12,088
Schedule of assumptions used in fair market valuations	The following inputs were used in the fair market valuation of the Convertible Note Hedges and Note Hedge Warrants as of December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ Year Ended ​ ​ ​ December 31, 2021 ​ December 31, 2020 ​ ​ ​ Convertible Note Hedge ​ Convertible Note Hedge ​ ​ Note Hedges ​ Warrants Note Hedges ​ Warrants Risk-free interest rate (1) ​ ​ 0.2 % ​ 0.4 % ​ 0.1 % ​ 0.1 % Expected term ​ 0.5 ​ 1.0 ​ ​ 1.5 ​ 2.0 ​ Stock price (2) ​ $ 11.66 ​ $ 11.66 ​ $ 11.39 ​ $ 11.39 ​ Strike price (3) ​ $ 14.51 ​ $ 18.82 ​ $ 14.51 ​ $ 18.82 ​ Common stock volatility (4) ​ ​ 27.0 % ​ 32.2 % ​ 46.7 % ​ 50.3 % Dividend yield (5) ​ — % — % — % — % (1) Based on U.S. Treasury yield curve, with terms commensurate with the expected terms of the Convertible Note Hedges and the Note Hedge Warrants. (2) The closing price of the Company’s Class A Common Stock on the last trading days of the years ended December 31, 2021 and 2020, respectively. (3) As per the respective agreements for the Convertible Note Hedges and Note Hedge Warrants. (4) Expected volatility based on historical volatility of the Company’s Class A Common Stock. (5) The Company has not paid and does not anticipate paying cash dividends on its shares of common stock in the foreseeable future; therefore, the expected dividend yield is assumed to be zero . ​
Schedule of the change in Level 3 convertible note derivatives	The following table reflects the change in the Company's Level 3 Convertible Note Hedges and Note Hedge Warrants from December 31, 2019 through December 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible ​ Note Hedge ​ Note Hedges Warrants Balance at December 31, 2019 ​ $ 31,366 ​ $ (24,260) Change in fair value, recorded as a component of (loss) gain on derivatives ​ ​ (18,301) ​ ​ 12,172 Balance at December 31, 2020 ​ $ 13,065 ​ $ (12,088) Change in fair value, recorded as a component of (loss) gain on derivatives ​ ​ (11,950) ​ ​ 10,772 Balance at December 31, 2021 ​ $ 1,115 ​ $ (1,316)

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Schedule of components of lease cost and supplemental cash flow information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ Operating lease cost (1) ​ $ 2,520 ​ $ 2,530 ​ $ 16,452 ​ Variable lease payments ​ ​ — ​ ​ — ​ ​ 1,526 ​ Short-term lease cost ​ ​ 960 ​ ​ 1,420 ​ ​ 1,512 ​ Total lease cost ​ $ 3,480 ​ $ 3,950 ​ $ 19,490 ​ (1) Operating lease cost is presented net of $0.3 million of sublease income for the year ended December 31, 2019 related to a sublease agreement between Ironwood and Cyclerion executed upon Separation. The sublease agreement terminated in May 2019. ​ Supplemental information related to leases for the periods reported is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ ​ Right-of-use assets obtained in exchange for new operating lease upon adoption of ASC 842 (in thousands) ​ ​ $ — ​ ​ $ — ​ ​ $ 88,299 ​ ​ Adjustment to right-of-use assets as a result of the lease modification upon Separation (in thousands) ​ ​ ​ — ​ ​ ​ — ​ ​ ​ (40,427) ​ ​ Adjustment to right-of-use assets as a result of the termination of the Binney Street Lease (in thousands) ​ ​ ​ — ​ ​ ​ — ​ ​ ​ (34,440) ​ ​ Right-of-use assets obtained in exchange for new operating lease liabilities upon execution of Summer Street Lease (in thousands) ​ ​ ​ — ​ ​ ​ — ​ ​ ​ 18,452 ​ ​ Cash paid for amounts included in the measurement of lease liabilities (in thousands) ​ ​ $ 3,128 ​ ​ $ 1,146 ​ ​ $ 18,598 ​ ​ Weighted-average remaining lease term of operating leases (in years) ​ ​ ​ 8.3 ​ ​ ​ 9.3 ​ ​ ​ 10.2 ​ ​ Weighted-average discount rate of operating leases ​ ​ ​ 5.8 % ​ ​ 5.8 % ​ ​ 5.8 % ​ ​
Schedule of future minimum lease payments under non-cancelable operating leases	Future minimum lease payments under non-cancelable operating leases as of December 31, 2021 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 ​ $ 3,129 2023 ​ ​ 3,065 2024 ​ ​ 3,126 2025 ​ 3,189 2026 ​ 3,252 2027 and thereafter ​ ​ 11,603 Total future minimum lease payments ​ ​ 27,364 Less: present value adjustment ​ ​ (5,753) Operating lease liabilities ​ ​ 21,611 Less: current portion of operating lease liabilities ​ ​ (3,127) Operating lease liabilities, net of current portion ​ $ 18,484

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Schedule of property and equipment	​ ​ ​ ​ ​ ​ Estimated Useful Life Asset Description (In Years) Laboratory equipment 5 ​ Computer and office equipment 3 ​ Furniture and fixtures 7 ​ Software 3 ​ ​ Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 2020 Software ​ $ 5,667 ​ $ 8,615 ​ Leasehold improvements ​ 7,407 ​ 7,407 ​ Laboratory equipment ​ 1,327 ​ 1,898 ​ Furniture and fixtures ​ 1,517 ​ 1,517 ​ Computer and office equipment ​ 1,285 ​ 1,297 ​ Total property and equipment ​ 17,203 ​ 20,734 ​ Less accumulated depreciation and amortization ​ (9,628) ​ (11,805) ​ Total property and equipment, net ​ $ 7,575 ​ $ 8,929 ​

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 2020 Accrued compensation and benefits ​ $ 16,653 ​ ​ 13,413 ​ Restructuring liabilities ​ ​ 462 ​ 10,510 ​ Stock repurchase ​ ​ 3,009 ​ ​ — ​ Other ​ 3,442 ​ ​ 2,563 ​ Total accrued expenses and other current liabilities ​ $ 23,566 ​ $ 26,486 ​

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Schedule of outstanding Convertible Note	The Company’s outstanding balances for the convertible senior notes as of December 31, 2021 and 2020 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2021 ​ 2020 ​ Liability component: ​ ​ ​ ​ ​ ​ Principal: ​ ​ ​ ​ ​ 2022 Convertible Notes $ 120,699 ​ $ 120,699 ​ 2024 Convertible Notes ​ 200,000 ​ ​ 200,000 ​ 2026 Convertible Notes ​ 200,000 ​ ​ 200,000 ​ Less: unamortized debt discount ​ (61,641) ​ ​ (83,900) ​ Less: unamortized debt issuance costs ​ (4,867) ​ ​ (6,543) ​ Net carrying amount $ 454,191 ​ $ 430,256 ​ Equity component: ​ ​ ​ ​ ​ ​ 2022 Convertible Notes ​ 19,807 ​ ​ 19,807 ​ 2024 Convertible Notes ​ 41,152 ​ ​ 41,152 ​ 2026 Convertible Notes ​ 51,350 ​ ​ 51,350 ​ Total equity component $ 112,309 ​ $ 112,309 ​
Schedule of interest expense related to Convertible Notes	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 ​ 2019 Contractual interest expense ​ $ 7,216 ​ $ 7,216 ​ $ 7,361 Amortization of debt issuance costs ​ ​ 1,678 ​ ​ 1,462 ​ ​ 1,190 Amortization of debt discount ​ ​ 22,256 ​ ​ 20,800 ​ ​ 17,683 Total interest expense ​ $ 31,150 ​ $ 29,478 ​ $ 26,234
Schedule of future minimum payments details of debt	​ ​ ​ ​ ​ ​ 2022 ​ $ 126,557 ​ 2023 ​ ​ 4,500 ​ 2024 ​ ​ 203,750 ​ 2025 ​ ​ 3,000 ​ 2026 ​ ​ 201,500 ​ Total future minimum payments under the convertible senior notes ​ 539,307 ​ Less: amounts representing interest ​ ​ (18,608) ​ Less: unamortized debt discount ​ ​ (61,641) ​ Less: unamortized debt issuance costs ​ ​ (4,867) ​ Convertible senior notes balance ​ $ 454,191 ​ ​

Employee Stock Benefit Plans (T

Employee Stock Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Summary of expense recognized for share-based compensation arrangements	The following table summarizes share-based compensation expense by award type (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Stock options ​ $ 3,154 ​ $ 7,680 ​ $ 12,526 ​ Time-based restricted stock units ​ ​ 14,539 ​ ​ 18,624 ​ ​ 15,488 ​ Performance-based restricted stock units ​ 1,295 ​ 2,190 ​ — ​ Restricted stock awards ​ 2,684 ​ 1,886 ​ 2,095 ​ Employee stock purchase plan ​ 419 ​ 722 ​ 1,115 ​ Stock awards ​ 190 ​ 73 ​ 54 ​ Total share-based compensation expense ​ $ 22,281 ​ $ 31,175 ​ $ 31,278 ​
Share-based compensation expense reflected in the condensed consolidated statements of operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Stock options ​ $ 3,154 ​ $ 7,680 ​ $ 12,526 ​ Time-based restricted stock units ​ ​ 14,539 ​ ​ 18,624 ​ ​ 15,488 ​ Performance-based restricted stock units ​ 1,295 ​ 2,190 ​ — ​ Restricted stock awards ​ 2,684 ​ 1,886 ​ 2,095 ​ Employee stock purchase plan ​ 419 ​ 722 ​ 1,115 ​ Stock awards ​ 190 ​ 73 ​ 54 ​ Total share-based compensation expense ​ $ 22,281 ​ $ 31,175 ​ $ 31,278 ​
Schedule of weighted-average assumptions used to estimate the fair value of Relative TSR PSUs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 Fair value of common stock ​ $ 11.39 ​ Expected volatility ​ 47.9 % Expected term (in years) ​ 2.6 ​ Risk-free interest rate ​ 0.3 % Expected dividend yield ​ — % ​
Summary of restricted stock activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested as of December 31, 2020 246,500 ​ $ 10.38 ​ Granted 230,160 ​ ​ 11.67 ​ Vested (213,400) ​ ​ 11.58 ​ Forfeited — ​ ​ — ​ Unvested as of December 31, 2021 263,260 ​ $ 11.61 ​ ​
Schedule of weighted-average assumptions used to estimate the fair value of the stock options using the Black-Scholes option-pricing model	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 ​ 2019 ​ Expected volatility ​ 46.6 % 46.3 % Expected term (in years) ​ 6.1 ​ 6.1 ​ Risk-free interest rate ​ 1.5 % 2.5 % Expected dividend yield ​ — % — %
Summary of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Weighted- ​ ​ ​ ​ ​ Number of ​ Average ​ Average ​ Aggregate ​ ​ Stock ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Options ​ Price (1) ​ Life ​ Value ​ ​ ​ ​ ​ ​ ​ (in years) ​ (in thousands) Outstanding at December 31, 2020 13,459,671 ​ $ 12.25 ​ 4.27 ​ $ 5,613 ​ Granted — ​ ​ — ​ — ​ ​ — ​ Exercised (1,698,362) ​ ​ 10.83 ​ — ​ ​ — ​ Cancelled (2,388,515) ​ ​ 13.07 ​ — ​ ​ — ​ Outstanding at December 31, 2021 9,372,794 ​ ​ 12.30 ​ 3.51 ​ ​ 4,528 ​ Vested or expected to vest at December 31, 2021 9,331,488 ​ ​ 12.31 ​ 3.49 ​ ​ 4,509 ​ Exercisable at December 31, 2021 8,972,651 ​ ​ 12.33 ​ 3.38 ​ ​ 4,385 ​ ​ (1) Exercise prices relating to stock options granted prior to the Separation have not been adjusted to reflect the effect of the Separation on the stock options. ​
Schedule of unrecognized share-based compensation expense, net of estimated forfeitures by type of awards and weighted-average period	​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized Weighted-Average ​ ​ Expense, Net ​ Remaining ​ ​ of Estimated ​ Recognition ​ ​ ​ Forfeitures ​ Period ​ ​ (in thousands) ​ (in years) Type of award: ​ ​ ​ ​ ​ ​ Stock options with time-based vesting ​ $ 1,541 ​ 1.14 ​ Restricted stock awards ​ ​ 1,464 ​ 0.60 ​ Time-based restricted stock units ​ ​ 22,545 ​ 2.46 ​ Performance-based restricted stock units ​ ​ 3,816 ​ 1.74 ​ Stock options with time-based and performance-based vesting ​ ​ — ​ — ​ ​
Time-based Restricted Stock Units
Table Text Blocks
Summary of RSU activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ Average ​ ​ ​ Number ​ Grant Date ​ ​ of RSUs Fair Value Outstanding as of December 31, 2020 4,170,626 ​ $ 11.90 ​ Granted ​ 2,707,427 ​ ​ 10.40 ​ Vested and released ​ (1,697,745) ​ ​ 12.18 ​ Forfeited ​ (1,316,200) ​ ​ 11.38 ​ Outstanding as of December 31, 2021 3,864,108 ​ $ 10.89 ​ ​
Performance-based Restricted Stock Units
Table Text Blocks
Summary of RSU activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ Average ​ ​ ​ Number ​ Grant Date ​ ​ of PSUs Fair Value Outstanding as of December 31, 2020 586,157 ​ $ 12.48 ​ Granted ​ 661,651 ​ ​ 14.65 ​ Vested and released ​ — ​ ​ — ​ Forfeited ​ (414,522) ​ ​ 12.76 ​ Outstanding as of December 31, 2021 833,286 ​ $ 14.06 ​ ​

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Schedule of the components of the provision for (benefit from) income taxes	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 ​ 2020 ​ 2019 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ — ​ $ — ​ $ — State ​ ​ 5,503 ​ ​ 2,685 ​ ​ — Total current ​ ​ 5,503 ​ ​ 2,685 ​ ​ — Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ ​ (251,367) ​ ​ — ​ ​ — State ​ ​ (81,927) ​ ​ — ​ ​ — Total deferred ​ ​ (333,294) ​ ​ — ​ ​ — Total income tax (benefit) expense ​ $ (327,791) ​ $ 2,685 ​ $ — ​
Reconciliation of income taxes from continuing operations computed using U.S. federal statutory rate to that reflected in operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2021 2020 2019 Income tax expense (benefit) using U.S. federal statutory rate ​ $ 42,138 ​ $ 22,861 ​ $ 4,517 ​ Permanent differences ​ 34 ​ 74 ​ 65 ​ State income taxes, net of federal benefit ​ 12,554 ​ 7,565 ​ (1,902) ​ Disallowed Separation related costs ​ ​ — ​ ​ — ​ ​ 4,658 ​ Executive compensation - Section 162(m) ​ ​ 695 ​ ​ 1,718 ​ ​ 662 ​ Meals and entertainment ​ ​ 349 ​ ​ 395 ​ ​ 495 ​ Non-deductible share-based compensation ​ 43 ​ (144) ​ (1,202) ​ Excess tax benefits ​ ​ 6,270 ​ ​ 5,132 ​ ​ 3,324 ​ Fair market valuation of Note Hedge Warrants and Convertible Note Hedges ​ ​ 325 ​ ​ 1,680 ​ ​ (290) ​ Tax credits ​ (9) ​ (3,149) ​ (4,374) ​ Expiring net operating losses and tax credits ​ 491 ​ 1,991 ​ 3,764 ​ Effect of change in state tax rate on deferred tax assets and deferred tax liabilities ​ 123 ​ (208) ​ (2,563) ​ Change in the valuation allowance ​ (390,804) ​ (35,230) ​ (7,154) ​ Income tax expense (benefit) ​ $ (327,791) ​ $ 2,685 ​ $ — ​ ​
Schedule of components of deferred tax assets and liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2021 2020 Deferred tax assets: ​ ​ ​ ​ ​ ​ ​ Net operating loss carryforwards ​ $ 165,022 ​ $ 234,772 ​ Tax credit carryforwards ​ 60,125 ​ 60,607 ​ Capitalized research and development ​ 4,981 ​ 7,498 ​ Share-based compensation ​ ​ 16,857 ​ ​ 21,848 ​ Basis difference on collaboration agreement for North America with AbbVie ​ ​ 78,194 ​ ​ 62,629 ​ Accruals and reserves ​ ​ 5,003 ​ ​ 6,114 ​ Basis difference on 2022 Convertible Notes ​ ​ 8,166 ​ ​ 6,183 ​ Intangible assets ​ ​ 5,396 ​ ​ — ​ Interest expense ​ ​ — ​ ​ 3,386 ​ Operating lease liability ​ ​ 5,971 ​ ​ 6,504 ​ Other ​ 3,997 ​ 5,049 ​ Total deferred tax assets ​ 353,712 ​ 414,590 ​ Deferred tax liabilities: ​ ​ ​ ​ ​ ​ ​ Basis difference on 2024 Convertible Notes ​ ​ (4,363) ​ ​ (5,951) ​ Basis difference on 2026 Convertible Notes ​ ​ (7,597) ​ ​ (9,022) ​ Operating lease right-of-use assets ​ ​ (4,248) ​ ​ (4,603) ​ Total deferred tax liabilities ​ ​ (16,208) ​ ​ (19,576) ​ Net deferred tax asset ​ ​ 337,504 ​ ​ 395,014 ​ Valuation allowance ​ (4,210) ​ (395,014) ​ Net deferred tax asset ​ $ 333,294 ​ $ — ​ ​
Summary of changes in the unrecognized tax benefits	The following table summarizes the changes in the Company’s unrecognized income tax benefits for the years ended December 31, 2021, 2020, and 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ Balance at the beginning of the period ​ $ 68,087 ​ $ 53,099 ​ $ 38,551 ​ Increases based on tax positions related to the current period ​ ​ 83,206 ​ ​ 66,687 ​ ​ 51,699 ​ Increases for tax positions related to prior periods ​ ​ — ​ ​ — ​ ​ 1,400 ​ Decreases for tax positions in prior periods ​ ​ (66,687) ​ ​ (51,699) ​ ​ (38,551) ​ Balance at the end of the period ​ $ 84,606 ​ $ 68,087 ​ $ 53,099 ​

Workforce Reduction and Restr_2

Workforce Reduction and Restructuring (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Schedule of charges made to the reduction in field-based workforce	The following table summarizes the accrued liabilities activity recorded in connection with the reduction in workforce in September 2020 and related restructuring activities during the year ended December 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ Accrued at ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued at ​ December 31, 2020 Charges ​ Amount Paid ​ Adjustments ​ December 31, 2021 Employee severance, benefits and related costs ​ $ 10,902 ​ $ 1,025 ​ $ (10,611) ​ $ (854) ​ $ 462 Contract related costs ​ ​ 5 ​ ​ 48 ​ ​ (53) ​ ​ — ​ ​ — Total $ 10,907 ​ $ 1,073 ​ $ (10,664) ​ $ (854) ​ $ 462 ​ The following table summarizes the accrued liabilities activity recorded in connection with the reductions in workforce and related restructuring activities during the year ended December 31, 2020 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts ​ ​ Accrued at ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued at ​ December 31, 2019 Charges ​ Amount Paid ​ Adjustments ​ December 31, 2020 Employee severance, benefits and related costs ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ February 2019 Reduction $ 75 ​ $ — ​ $ (75) ​ $ — ​ $ — September 2020 Reduction ​ ​ — ​ ​ 11,563 ​ ​ (661) ​ ​ — ​ ​ 10,902 Total $ 75 ​ $ 11,563 ​ $ (736) ​ $ — ​ $ 10,902 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contract related costs ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ August 2018 Reduction ​ $ 104 ​ $ — ​ $ — ​ $ (104) ​ $ — September 2020 Reduction ​ ​ — ​ ​ 108 ​ ​ (103) ​ ​ — ​ ​ 5 Total $ 104 ​ $ 108 ​ $ (103) ​ $ (104) ​ $ 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2021
Table Text Blocks
Selected Quarterly Financial Data (Unaudited)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First ​ Second ​ Third ​ Fourth ​ Total ​ ​ Quarter ​ Quarter ​ Quarter ​ Quarter ​ Year ​ ​ (in thousands, except per share data) 2021 ​ ​ ​ ​ ​ Total revenues ​ $ 88,845 ​ $ 104,031 ​ $ 103,747 ​ $ 117,130 ​ $ 413,753 ​ Total cost and expenses ​ 43,447 ​ 38,933 ​ ​ 38,576 ​ ​ 60,538 ​ 181,494 ​ Other expense, net ​ (5,040) ​ (10,726) ​ ​ (5,499) ​ ​ (10,337) ​ (31,602) ​ Net income and comprehensive income ​ 39,926 ​ 391,303 ​ ​ 55,845 ​ ​ 41,374 ​ 528,448 ​ Net income per share—basic ​ ​ 0.25 ​ ​ 2.42 ​ ​ 0.34 ​ ​ 0.25 ​ ​ 3.26 ​ Net income per share—diluted ​ ​ 0.25 ​ ​ 2.39 ​ ​ 0.34 ​ ​ 0.25 ​ ​ 3.21 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First ​ Second ​ Third ​ Fourth ​ Total ​ ​ Quarter ​ Quarter ​ Quarter ​ Quarter ​ Year ​ ​ (in thousands, except per share data) 2020 ​ ​ ​ ​ ​ Total revenues ​ $ 79,943 ​ $ 89,432 ​ $ 103,468 ​ $ 116,680 ​ $ 389,523 ​ Total cost and expenses ​ 66,716 ​ 56,719 ​ 57,852 ​ 65,296 ​ 246,583 ​ Other expense, net ​ (9,882) ​ (7,509) ​ (9,804) ​ (6,884) ​ (34,079) ​ Net income and comprehensive income ​ 3,345 ​ 25,204 ​ 34,423 ​ 43,204 ​ 106,176 ​ Net income per share—basic ​ ​ 0.02 ​ ​ 0.16 ​ ​ 0.22 ​ ​ 0.27 ​ ​ 0.67 ​ Net income per share—diluted ​ ​ 0.02 ​ ​ 0.16 ​ ​ 0.21 ​ ​ 0.27 ​ ​ 0.66 ​ ​

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Segment Information (Details) - segment	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment information
Number of reportable segments	1	1	1

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Cash and Cash Equivalents
Cash Equivalent included in cash and cash equivalent	$ 595.2	$ 349

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Cash [Abstract]
Restricted cash	$ 1,735	$ 2,220	$ 2,221
Restricted cash, current	1,250	1,735
Restricted cash, noncurrent	$ 485	$ 485

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Concentrations of Credit Risk (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts receivable | Accounts receivable balances | AbbVie
Concentrations
Concentration risk percentage (as a percent)	81.00%	76.00%
Accounts receivable | Accounts receivable balances | Astellas Pharma Inc.
Concentrations
Concentration risk percentage (as a percent)	1.00%	1.00%
Revenue from Contract with Customer Benchmark | Revenue | AbbVie
Concentrations
Concentration risk percentage (as a percent)	98.00%	96.00%	78.00%
Revenue from Contract with Customer Benchmark | Revenue | Astellas Pharma Inc.
Concentrations
Concentration risk percentage (as a percent)	1.00%	1.00%	13.00%

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2021
Laboratory equipment
Property and Equipment
Estimated useful life	5 years
Computer and office equipment
Property and Equipment
Estimated useful life	3 years
Furniture and fixtures
Property and Equipment
Estimated useful life	7 years
Software
Property and Equipment
Estimated useful life	3 years

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Leases (Details)	12 Months Ended
	Dec. 31, 2021
Leases
Lease, Practical Expedients, Package	true
Lease, Practical Expedient, Lessor Single Lease Component	true

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Derivative Assets and Liabilities (Details) - Convertible Senior Notes	Sep. 16, 2019	Aug. 12, 2019	Jun. 30, 2015
2.25% Convertible Senior Notes due 2022
Notes Payable
Stated interest rate (as a percent)	2.25%		2.25%
0.75% Convertible Senior Notes due 2024
Notes Payable
Stated interest rate (as a percent)		0.75%
1.50% Convertible Senior Notes due 2026
Notes Payable
Stated interest rate (as a percent)		1.50%

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Revenue Recognition (Details)	12 Months Ended
	Dec. 31, 2021
U.S. | AbbVie
Collaboration agreements
Percentage of the pre-tax net profit or loss (as a percent)	50.00%

Summary of Significant Accou_12

Summary of Significant Accounting Policies - Patent Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Patent Costs
Selling, general and administrative	$ 111,133	$ 140,003	$ 172,450
Patents
Patent Costs
Selling, general and administrative	$ 1,700	$ 2,300	$ 7,800

Summary of Significant Accou_13

Summary of Significant Accounting Policies - New Accounting Pronouncements (Details)	12 Months Ended
	Dec. 31, 2021
Accounting Standards Update 2016-02
New Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2019
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected	us-gaap:AccountingStandardsUpdate201602CumulativeEffectPeriodOfAdoptionMember
Accounting Standards Update 2019-12
New Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2021
Change in Accounting Principle, Accounting Standards Update, Early Adoption	false
Accounting Standards Update 2020-06
New Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	false
Accounting Standards Update 2021-04
New Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	false

Cyclerion Separation - Separati

Cyclerion Separation - Separation Agreement (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Apr. 01, 2019
Assets:
Prepaid expenses and other current assets	$ 8,689	$ 9,189
Property and equipment, net	7,575	8,929
Other assets	1,000	943
Total assets	1,126,927	559,238
Liabilities:
Accrued research and development costs	15,896	1,898
Accrued expenses and other current liabilities	$ 23,566	$ 26,486
Cyclerion Therapeutics, Inc.
Assets:
Prepaid expenses and other current assets			$ 1,169
Property and equipment, net			10,241
Other assets			21
Total assets			11,431
Liabilities:
Accrued research and development costs			5,673
Accrued expenses and other current liabilities			3,149
Total liabilities			8,822
Net Assets Transferred to Cyclerion			$ 2,609

Cyclerion Separation - Related

Cyclerion Separation - Related Party Information (Details) - Affiliated Entity - Cyclerion Therapeutics, Inc. $ in Millions	12 Months Ended
	Dec. 31, 2021agreement	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Cyclerion Separation
Tenant improvement reimbursement provisions received			$ 1.3
Incremental stock-based compensation expense			0
Transition services agreements | agreement	2
Other income for services provided to related party			0.3
Research and development
Cyclerion Separation
Expense for service provided by related party		$ 2.3	$ 4.5

Cyclerion Separation - Summary

Cyclerion Separation - Summary of Expenses (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Net Loss from Discontinued Operations
Net loss from discontinued operations	$ 37,438
sGC Business | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Net Loss from Discontinued Operations
Net loss from discontinued operations	37,438
Research and development | sGC Business | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Net Loss from Discontinued Operations
Net loss from discontinued operations	21,792
Selling, general and administrative | sGC Business | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Net Loss from Discontinued Operations
Net loss from discontinued operations	$ 15,646

Cyclerion Separation - Summar_2

Cyclerion Separation - Summary of Assets and Liabilities Held for Disposition (Details) - Discontinued Operations, Disposed of by Means Other than Sale, Spinoff - sGC Business - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Assets	$ 0	$ 0
Liabilities:
Liabilities	$ 0	$ 0

Net Income Per Share - Computat

Net Income Per Share - Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income	$ 41,374	$ 55,845	$ 391,303	$ 39,926	$ 43,204	$ 34,423	$ 25,204	$ 3,345	$ 528,448	$ 106,176	$ 21,505
Net income (loss) available to common stockholders, basic									528,448	106,176	21,505
Net income (loss) available to common stockholders, diluted									$ 528,448	$ 106,176	$ 21,505
Denominator:
Weighted average number of common shares outstanding used in computing net income per share - basic (in shares)									162,245	159,427	156,023
Effect of dilutive securities:
Weighted average number of common shares outstanding used in computing net income per share - diluted (in shares)									164,418	160,655	156,023
Net income per share - basic (in dollars per share)	$ 0.25	$ 0.34	$ 2.42	$ 0.25	$ 0.27	$ 0.22	$ 0.16	$ 0.02	$ 3.26	$ 0.67	$ 0.14
Net income per share - diluted (in dollars per share)	$ 0.25	$ 0.34	$ 2.39	$ 0.25	$ 0.27	$ 0.21	$ 0.16	$ 0.02	$ 3.21	$ 0.66	$ 0.14
Employee stock options
Effect of dilutive securities:
Effect of dilutive securities									488	367
Time-based Restricted Stock Units
Effect of dilutive securities:
Effect of dilutive securities									1,422	766
Performance-based Restricted Stock Units
Effect of dilutive securities:
Effect of dilutive securities									146	1
Restricted Stock
Effect of dilutive securities:
Effect of dilutive securities									117	94

Net Income Per Share - Potentia

Net Income Per Share - Potentially Dilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	54,428	58,554	67,087
Employee stock options
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	7,701	11,746	17,194
Restricted Stock
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)		2	182
Time-based Restricted Stock Units
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	102	209	3,207
Performance-based Restricted Stock Units
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	121	93
Note Hedge Warrants
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	8,318	8,318	8,318
2.25% Convertible Senior Notes due 2022
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	8,318	8,318	8,318
0.75% Convertible Senior Notes due 2024
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	14,934	14,934	14,934
1.50% Convertible Senior Notes due 2026
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	14,934	14,934	14,934

Collaboration, License, and O_3

Collaboration, License, and Other Agreements - Summary (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Revenue	$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Collaborative arrangements revenue
Revenues:
Revenue									412,784	381,545	379,652
Collaborative arrangement, other agreements
Revenues:
Revenue									1,755	1,335	1,845
Sale of active pharmaceutical ingredient
Revenues:
Revenue									969	7,978	48,761
AbbVie | Collaborative arrangement, co-promotion agreements
Revenues:
Revenue											3,723
AbbVie | Sale of active pharmaceutical ingredient
Revenues:
Revenue									223	421
AbbVie | North America | Collaborative arrangements revenue
Revenues:
Revenue									403,085	370,902	327,591
AbbVie | North America | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue									403,085	370,902	327,591
AbbVie | Europe and Other | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue									2,558	2,196	1,718
AstraZeneca | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue									743	682	32,628
AstraZeneca | Sale of active pharmaceutical ingredient
Revenues:
Revenue									597	5,540	2,973
Astellas Pharma Inc. | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue									2,232	2,128	10,147
Astellas Pharma Inc. | Sale of active pharmaceutical ingredient
Revenues:
Revenue									149	2,017	45,788
Alnylam | Collaborative arrangement, co-promotion agreements
Revenues:
Revenue									$ 2,411	$ 4,302	$ 2,000

Collaboration, License, and O_4

Collaboration, License, and Other Agreements - Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts receivable, net
Accounts receivable, net	$ 138	$ 145.8
Accounts receivable, net of accounts payable	112.2	110.9
AbbVie
Accounts receivable, net
Accounts payable	$ 5	$ 4.3

Collaboration, License, and O_5

Collaboration, License, and Other Agreements - North America - General Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)itempayment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Collaboration, License, Promotion and Other Commercial Agreements
Sales-related milestone if certain conditions are met	$ 80,000
Research and development expense	70,405	$ 88,062	$ 115,044
AbbVie
Collaboration, License, Promotion and Other Commercial Agreements
Cumulative license fees and development milestone payments received	$ 205,000
Number of milestone payments received | payment	6
Equity investment in the entity's capital stock	$ 25,000
Remaining commercial-period performance obligations | item	3
Cost sharing amount, reduction to research and development	$ 11,500	5,600	7,200
Collaborative arrangement, percentage of obligation of development costs incurred	50.00%
Percentage of net profit from commercialization (as a percent)	50.00%
Percentage of net loss from commercialization (as a percent)	50.00%
North America
Collaboration, License, Promotion and Other Commercial Agreements
Research and development expense	$ 8,200	$ 20,100	$ 37,600

Collaboration, License, and O_6

Collaboration, License, and Other Agreements - North America - Collaborative Arrangements Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Revenue	$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Collaborative arrangements revenue
Revenues:
Revenue									412,784	381,545	379,652
AbbVie | North America | Collaborative arrangements revenue
Revenues:
Revenue									403,085	370,902	327,591
AbbVie | North America | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue									403,085	370,902	327,591
AbbVie | North America | Collaborative arrangements, LINZESS
Revenues:
Revenue									400,371	368,603	325,429
AbbVie | North America | Royalty
Revenues:
Revenue									$ 2,714	$ 2,299	$ 2,162

Collaboration, License, and O_7

Collaboration, License, and Other Agreements - North America - Commercial Efforts (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Selling, general and administrative									111,133	140,003	172,450
AbbVie | U.S.
Collaboration, License, Promotion and Other Commercial Agreements
Patent prosecution and patent litigation costs									300	600	2,400
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue									412,784	381,545	379,652
Collaborative arrangements, LINZESS | AbbVie | U.S.
Collaboration, License, Promotion and Other Commercial Agreements
Selling, general and administrative									$ 30,300	$ 39,900	$ 40,500

Collaboration, License, and O_8

Collaboration, License, and Other Agreements - North America - Royalty Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Revenue	$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Collaborative arrangements revenue
Revenues:
Revenue									412,784	381,545	379,652
Collaborative arrangements revenue | North America | AbbVie
Revenues:
Revenue									403,085	370,902	327,591
Collaborative arrangement, collaboration and license agreements | North America | AbbVie
Revenues:
Revenue									403,085	370,902	327,591
Royalty | North America | AbbVie
Revenues:
Revenue									2,714	2,299	2,162
Royalty | Canada and Mexico | AbbVie
Revenues:
Revenue									$ 2,700	$ 2,300	$ 2,200

Collaboration, License, and O_9

Collaboration, License, and Other Agreements - European and Other Territories (Details) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2021

Sep. 30, 2021

Jun. 30, 2021

Mar. 31, 2021

Dec. 31, 2020

Sep. 30, 2020

Jun. 30, 2020

Mar. 31, 2020

Dec. 31, 2021

Dec. 31, 2020

Dec. 31, 2019

Oct. 31, 2015

Sep. 30, 2012

Collaboration, License, Promotion and Other Commercial Agreements

Revenue

$ 117,130

$ 103,747

$ 104,031

$ 88,845

$ 116,680

$ 103,468

$ 89,432

$ 79,943

$ 413,753

$ 389,523

$ 428,413

Collaborative arrangements revenue

Collaboration, License, Promotion and Other Commercial Agreements

Revenue

412,784

381,545

379,652

Collaborative arrangement, collaboration and license agreements | AbbVie | Europe and Other

Collaboration, License, Promotion and Other Commercial Agreements

Revenue

$ 2,558

2,196

1,718

License | AbbVie

Collaboration, License, Promotion and Other Commercial Agreements

Remaining milestone payment due upon the amendment to the license agreement

$ 42,500

Royalty percentage, five years following the first commercial sale

upper-single digits

Annual royalty

5 years

Royalty percentage, thereafter

low-double digits

Royalty percentage, expanded territory

lower-single digits

Revenue remaining performance obligation

$ 0

Royalty | AbbVie | Europe and Other

Collaboration, License, Promotion and Other Commercial Agreements

Revenue

$ 2,600

$ 2,200

$ 1,700

Collaboration, License, and _10

Collaboration, License, and Other Agreements - Japan (Details) $ in Thousands	Aug. 01, 2019USD ($)	Nov. 30, 2009USD ($)payment	Dec. 31, 2021USD ($)	Sep. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2017USD ($)
Collaboration, License, Promotion and Other Commercial Agreements
Revenue			$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Astellas Pharma Inc., 2009 License Agreement
Collaboration, License, Promotion and Other Commercial Agreements
Up-front fee received		$ 30,000
Number of milestone payments | payment		3
Milestone payments received		$ 45,000
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue											412,784	381,545	379,652
Collaborative arrangement, collaboration and license agreements | Astellas Pharma Inc.
Collaboration, License, Promotion and Other Commercial Agreements
Revenue											2,232	2,128	10,147
Collaborative arrangement, collaboration and license agreements | Astellas Pharma Inc., 2009 License Agreement, Amended 2019
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 20,400
Non-refundable upfront payment	$ 10,000
Collaborative arrangement, collaboration and license agreements, upfront fee | Astellas Pharma Inc., 2009 License Agreement, Amended 2019
Collaboration, License, Promotion and Other Commercial Agreements
Revenue													10,000
Royalty | Astellas Pharma Inc., 2009 License Agreement, Amended 2019
Collaboration, License, Promotion and Other Commercial Agreements
Revenue											2,200	2,100
Sale of active pharmaceutical ingredient
Collaboration, License, Promotion and Other Commercial Agreements
Revenue											969	7,978	48,761
Sale of active pharmaceutical ingredient | Astellas Pharma Inc.
Collaboration, License, Promotion and Other Commercial Agreements
Revenue											149	2,017	45,788
Sale of active pharmaceutical ingredient | Astellas Pharma Inc., 2009 License Agreement
Collaboration, License, Promotion and Other Commercial Agreements
Revenue													27,500
Revenue remaining performance obligation														$ 0
Sale of active pharmaceutical ingredient | Astellas Pharma Inc., 2009 License Agreement, Amended 2019
Collaboration, License, Promotion and Other Commercial Agreements
Revenue											$ 200	$ 2,000	$ 18,300

Collaboration, License, and _11

Collaboration, License, and Other Agreements - China, Hong Kong and Macau (Details) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Jan. 31, 2021USD ($)	Dec. 31, 2021USD ($)	Sep. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2021USD ($)installment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										412,784	381,545	379,652
Sale of active pharmaceutical ingredient
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										969	7,978	48,761
AstraZeneca
Collaboration, License, Promotion and Other Commercial Agreements
Milestone payment to be received by company upon milestone achievement										$ 90,000
Percentage of net loss from commercialization (as a percent)										55.00%
Pre-launch commercial services and supply chain services												1,200
Amount of non-contingent arrangement consideration										$ 35,000
Non-contingent consideration installments | installment										3
Non-contingent arrangement consideration installment received	$ 10,000
Percentage of tiered royalties										20.00%
Interest income										$ 600	800	200
AstraZeneca | Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Collaborative arrangement, significant financing component, transaction price		2,600								2,600
Collaborative arrangement, expected interest income		$ 2,600								2,600
AstraZeneca | Collaborative arrangement, collaboration and license agreements
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										743	682	32,628
AstraZeneca | License
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										32,400		32,400
AstraZeneca | Collaborative arrangement, transition services agreement
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										200	600	200
AstraZeneca | Royalty
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										500	100
AstraZeneca | Sale of active pharmaceutical ingredient
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										$ 597	$ 5,540	$ 2,973

Collaboration, License, and _12

Collaboration, License, and Other Agreements - Other Collaboration and License Agreements (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Research and development expense									70,405	88,062	115,044
Accrued research and development costs	15,896				1,898				15,896	1,898
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue									412,784	381,545	379,652
Alnylam | Collaborative arrangement, co-promotion agreements
Collaboration, License, Promotion and Other Commercial Agreements
Total annual service fees due					$ 5,500					5,500
Revenue									2,411	4,302	2,000
Alnylam | Service fees
Collaboration, License, Promotion and Other Commercial Agreements
Revenue										3,500	$ 2,000
Alnylam | Royalty
Collaboration, License, Promotion and Other Commercial Agreements
Revenue									2,400	$ 800
COUR Pharmaceuticals Development Company, Inc.
Collaboration, License, Promotion and Other Commercial Agreements
Collaborative arrangement, upfront payment									6,000
Collaborative arrangement, contingent payment, payable	13,500								13,500
Collaborative arrangement, option to acquire license, exercise price, payable	35,000								35,000
Collaborative arrangement, milestones. potential commercial milestone payments, term of agreement, payable	440,000								440,000
Research and development expense									19,500
Accrued research and development costs	$ 13,500								$ 13,500

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - General Information (Details)	Dec. 31, 2021
Fair Value of Financial Instruments
Threshold percentage of collateralized value (as a percent)	102.00%

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Measured on Recurring Basis (Details) - Recurring basis - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Convertible note hedges	$ 1,115	$ 13,065
Total assets measured at fair value	598,083	364,300
Liabilities:
Note hedge warrants	1,316	12,088
Total liabilities measured at fair value	1,316	12,088
Money market funds
Assets:
Cash and cash equivalents	595,233	349,014
Restricted cash	1,735	2,221
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets measured at fair value	596,968	351,235
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets:
Cash and cash equivalents	595,233	349,014
Restricted cash	1,735	2,221
Significant Unobservable Inputs (Level 3)
Assets:
Convertible note hedges	1,115	13,065
Total assets measured at fair value	1,115	13,065
Liabilities:
Note hedge warrants	1,316	12,088
Total liabilities measured at fair value	$ 1,316	$ 12,088

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Transfers Between Fair Value Measurement Levels (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair value transfers
Fair value transfer between measurement levels	$ 0	$ 0	$ 0

Fair Value of Financial Instr_6

Fair Value of Financial Instruments - Assumptions - Convertible Note Hedges (Details)	Dec. 31, 2021$ / sharesY	Dec. 31, 2020$ / sharesY
Fair Value of Financial Instruments
Derivative asset, valuation technique	us-gaap:ValuationTechniqueOptionPricingModelMember	us-gaap:ValuationTechniqueOptionPricingModelMember
Measurement Input, Risk Free Interest Rate
Fair Value of Financial Instruments
Derivative asset, measurement input	0.002	0.001
Measurement Input, Expected Term
Fair Value of Financial Instruments
Derivative asset, measurement input | Y	0.5	1.5
Measurement Input, Share Price
Fair Value of Financial Instruments
Derivative asset, measurement input	11.66	11.39
Measurement Input, Exercise Price
Fair Value of Financial Instruments
Derivative asset, measurement input	14.51	14.51
Measurement Input, Price Volatility
Fair Value of Financial Instruments
Derivative asset, measurement input	0.270	0.467
Measurement Input, Expected Dividend Rate
Fair Value of Financial Instruments
Derivative asset, measurement input	0	0

Fair Value of Financial Instr_7

Fair Value of Financial Instruments - Assumptions - Note Hedge Warrants (Details)	Dec. 31, 2021$ / sharesY	Dec. 31, 2020$ / sharesY
Fair Value of Financial Instruments
Derivative liability, valuation technique	us-gaap:ValuationTechniqueOptionPricingModelMember	us-gaap:ValuationTechniqueOptionPricingModelMember
Measurement Input, Risk Free Interest Rate
Fair Value of Financial Instruments
Derivative liability, measurement input	0.004	0.001
Measurement Input, Expected Term
Fair Value of Financial Instruments
Derivative liability, measurement input | Y	1	2
Measurement Input, Share Price
Fair Value of Financial Instruments
Derivative liability, measurement input	11.66	11.39
Measurement Input, Exercise Price
Fair Value of Financial Instruments
Derivative liability, measurement input	18.82	18.82
Measurement Input, Price Volatility
Fair Value of Financial Instruments
Derivative liability, measurement input	0.322	0.503
Measurement Input, Expected Dividend Rate
Fair Value of Financial Instruments
Derivative liability, measurement input	0	0

Fair Value of Financial Instr_8

Fair Value of Financial Instruments - Change in Level 3 - Convertible Note Hedges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Change in Level 3 Assets
Balance at beginning of period	$ 13,065	$ 31,366
Change in fair value, recorded as a component of (loss) gain on derivatives	(11,950)	(18,301)
Balance at end of period	$ 1,115	$ 13,065

Fair Value of Financial Instr_9

Fair Value of Financial Instruments - Change in Level 3 - Note Hedge Warrants (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Change in Level 3 Liabilities
Balance at beginning of period	$ (12,088)	$ (24,260)
Change in fair value, recorded as a component of gain (loss) on derivatives	10,772	12,172
Balance at end of period	$ (1,316)	$ (12,088)

Fair Value of Financial Inst_10

Fair Value of Financial Instruments - Notes Payable (Details) - Convertible Senior Notes - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Aug. 31, 2019	Jun. 30, 2015
2.25% Convertible Senior Notes due 2022
Fair value disclosures
Aggregate principal amount of notes issued	$ 120,699	$ 120,699		$ 335,700
Debt redeemed/repurchased			$ 215,000
2.25% Convertible Senior Notes due 2022 | Significant Other Observable Inputs (Level 2)
Fair value disclosures
Estimated fair value	125,200	130,200
0.75% Convertible Senior Notes due 2024
Fair value disclosures
Aggregate principal amount of notes issued	200,000	200,000	200,000
0.75% Convertible Senior Notes due 2024 | Significant Other Observable Inputs (Level 2)
Fair value disclosures
Estimated fair value	221,900	222,300
1.50% Convertible Senior Notes due 2026
Fair value disclosures
Aggregate principal amount of notes issued	200,000	200,000	$ 200,000
1.50% Convertible Senior Notes due 2026 | Significant Other Observable Inputs (Level 2)
Fair value disclosures
Estimated fair value	$ 227,200	$ 224,100

Fair Value of Financial Inst_11

Fair Value of Financial Instruments - Capped Calls with Respect to 2024 Convertible Notes and 2026 Convertible Notes (Details) - Capped Calls with Respect to 2024 Convertible Notes and 2026 Convertible Notes	1 Months Ended
	Aug. 31, 2019$ / shares$ / itemshares
Capped Calls
Number of shares covered by capped calls (in shares) | shares	29,867,480
Strike price (in dollars per share) | $ / shares	$ 13.39
Cap price | $ / item	17.05

Leases - General Information (D

Leases - General Information (Details) - Accounting Standards Update 2016-02	12 Months Ended
	Dec. 31, 2021
New Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2019
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected	us-gaap:AccountingStandardsUpdate201602CumulativeEffectPeriodOfAdoptionMember

Leases - Vehicle Fleet Leases (

Leases - Vehicle Fleet Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating leases
Restricted cash	$ 1,735	$ 2,220	$ 2,221
Vehicles, 2018 Vehicle Leases
Operating leases
Restricted cash	$ 1,700	$ 2,200

Leases - Lease Cost - Tabular D

Leases - Lease Cost - Tabular Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lease cost
Operating lease cost	$ 2,520	$ 2,530	$ 16,452
Variable lease payments			1,526
Short-term lease cost	960	1,420	1,512
Total lease cost	$ 3,480	$ 3,950	$ 19,490

Leases - Lease Cost - Sublease

Leases - Lease Cost - Sublease Income (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Lease cost
Sublease income	$ 0.3

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating leases
Right-of-use assets obtained in exchange for new operating lease upon adoption of ASC 842			$ 88,299
Adjustment to right-of-use assets as a result of the lease modification upon Separation			(40,427)
Adjustment to right-of-use assets as a result of the termination of the Binney Street Lease			(34,440)
Right-of-use assets obtained in exchange for new operating lease liabilities upon execution of Summer Street Lease			18,452
Cash paid for amounts included in the measurement of lease liabilities	$ 3,128	$ 1,146	$ 18,598
Weighted-average remaining lease term of operating leases (in years)	8 years 3 months 18 days	9 years 3 months 18 days	10 years 2 months 12 days
Weighted-average discount rate of operating leases (as a percent)	5.80%	5.80%	5.80%

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2021USD ($)
Future minimum lease payments
2022	$ 3,129
2023	3,065
2024	3,126
2025	3,189
2026	3,252
2027 and thereafter	11,603
Total future minimum lease payments	$ 27,364

Leases - Operating Lease Obliga

Leases - Operating Lease Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating lease obligations
Total future minimum lease payments	$ 27,364
Less: present value adjustment	(5,753)
Operating lease liabilities	21,611
Less: current portion of operating lease liabilities	(3,127)	$ (3,128)
Operating lease liabilities, net of current portion	$ 18,484	$ 20,318

Leases - Summer Street Lease (D

Leases - Summer Street Lease (Details) ft² in Thousands, $ in Thousands	Jun. 11, 2019ft²	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Operating leases
Weighted-average discount rate of operating leases (as a percent)		5.80%	5.80%	5.80%
Operating lease right-of-use assets		$ 15,350	$ 16,576
Operating lease liability		21,611
Operating lease cost		$ 2,520	2,530	$ 16,452
Summer Street Lease
Operating leases
Rentable area leased (in square feet) | ft²	39
Annual rent escalation (as a percent)	2.00%
Option to extend the term of the lease	true
Operating lease, renewal term	5 years
Weighted-average discount rate of operating leases (as a percent)		5.80%
Operating lease right-of-use assets		$ 15,300	16,600
Operating lease cost		2,500	2,500	$ 1,500
Lease liability, net of tenant improvement allowance reimbursement		$ 21,500	$ 23,200

Leases - Binney Street Lease (D

Leases - Binney Street Lease (Details) $ in Thousands	Jun. 11, 2019USD ($)ft²	Apr. 01, 2019ft²	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Jan. 01, 2019USD ($)
Operating leases
Weighted-average discount rate of operating leases (as a percent)			5.80%	5.80%	5.80%
Operating lease cost			$ 2,520	$ 2,530	$ 16,452
Sublease income					300
Restricted cash, noncurrent			485	485
Operating lease right-of-use assets			15,350	$ 16,576
Operating lease liability			$ 21,611
Binney Street Lease
Operating leases
Rentable area leased (in square feet) | ft²	108,000	108,000
Surrendered space (in square feet) | ft²		114,000
Weighted-average discount rate of operating leases (as a percent)	4.00%	5.10%
Gain on modification of lease					3,200
Lease termination cost	$ 9,000
Operating lease cost					16,300
Sublease income					$ 300
Operating lease right-of-use assets						$ 87,700
Operating lease liability						$ 94,300

Property and Equipment - Tabula

Property and Equipment - Tabular Disclosure (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property and Equipment
Property and equipment, gross	$ 17,203	$ 20,734
Less accumulated depreciation and amortization	(9,628)	(11,805)
Property and equipment, net	7,575	8,929
Software
Property and Equipment
Property and equipment, gross	5,667	8,615
Leasehold improvements
Property and Equipment
Property and equipment, gross	7,407	7,407
Laboratory equipment
Property and Equipment
Property and equipment, gross	1,327	1,898
Furniture and fixtures
Property and Equipment
Property and equipment, gross	1,517	1,517
Computer and office equipment
Property and Equipment
Property and equipment, gross	$ 1,285	$ 1,297

Property and Equipment - Deprec

Property and Equipment - Depreciation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property and Equipment
Depreciation and amortization	$ 1.5	$ 2.3	$ 5.6

Property and Equipment - Restru

Property and Equipment - Restructuring (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Reduction in Workforce, Discontinued Development of IW-3718, September 29, 2020
Impairment of Long-Lived Assets
Impairment of long-lived assets	$ 1.2

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Tabular Disclosure (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Expenses
Accrued compensation and benefits	$ 16,653	$ 13,413
Restructuring liabilities	462	10,510
Stock repurchase	3,009
Other	3,442	2,563
Total accrued expenses and other current liabilities	$ 23,566	$ 26,486

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Expenses
Other accrued expenses	$ 3,442	$ 2,563
Other accrued liabilities, uninvoiced vendor liabilities	2,700	2,100
Accrued interest	300	$ 300
Income taxes payable	$ 200

Notes Payable - General Informa

Notes Payable - General Information (Details)	Aug. 31, 2019USD ($)	Apr. 15, 2019USD ($)$ / sharesshares	Aug. 31, 2019USD ($)	Jun. 30, 2015USD ($)$ / sharesshares	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2019USD ($)	Dec. 31, 2020USD ($)	Sep. 16, 2019
Notes Payable
Payments for convertible note hedges			$ 25,200,000	$ 21,100,000
Net proceeds received						$ 400,000,000
Proceeds from partial termination of convertible note hedges and note hedge warrants			3,200,000
Loss on extinguishment of debt						30,977,000
Equity component of convertible senior notes						$ 92,502,000
Convertible Note Hedge
Notes Payable
Conversion price (in dollars per share) | $ / shares		$ 14.51			$ 16.58
Shares issuable upon conversion of debt (in shares) | shares					20,249,665
2.25% Convertible Senior Notes due 2022 | Note Hedge Warrants
Notes Payable
Shares issuable upon conversion of debt (in shares) | shares		23,135,435
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued				335,700,000	$ 120,699,000		$ 120,699,000
Net proceed received				324,000,000
Fees and expenses				$ 11,700,000
Stated interest rate (as a percent)				2.25%				2.25%
Conversion rate, number of shares to be issued per		68.9172		60.3209
Principal amount used for debt instrument conversion ratio		$ 1,000		$ 1,000
Conversion price (in dollars per share) | $ / shares		$ 14.51		$ 16.58
Shares issuable upon conversion of debt (in shares) | shares		23,135,435		20,249,665
Repurchase price, as percentage of principal amount, if company undergoes change of control				100.00%
Maximum period of the sole remedy for event failures in the Indenture					180 days
Amortization period				7 years
Debt redeemed/repurchased	$ 215,000,000		215,000,000
Debt redemption/repurchase price	227,300,000		227,300,000
Loss on extinguishment of debt	$ 23,400,000		23,400,000
Equity component of convertible senior notes			27,000,000
Initial debt issuance costs			$ 2,800,000
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes | Minimum
Notes Payable
Percentage of aggregate principal amount payable, in case of event of default				25.00%

Notes Payable - Convertible Sen

Notes Payable - Convertible Senior Notes - Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Aug. 31, 2019	Jun. 30, 2015
Liability component:
Less: unamortized debt discount	$ (61,641)
Less: unamortized debt issuance costs	(4,867)
Net carrying amount	454,191
Convertible Senior Notes
Liability component:
Less: unamortized debt discount	(61,641)	$ (83,900)
Less: unamortized debt issuance costs	(4,867)	(6,543)
Net carrying amount	454,191	430,256
Total equity component	112,309	112,309
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes
Liability component:
Aggregate principal amount of notes issued	120,699	120,699		$ 335,700
Total equity component	19,807	19,807
0.75% Convertible Senior Notes due 2024 | Convertible Senior Notes
Liability component:
Aggregate principal amount of notes issued	200,000	200,000	$ 200,000
Total equity component	41,152	41,152
1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes
Liability component:
Aggregate principal amount of notes issued	200,000	200,000	$ 200,000
Total equity component	$ 51,350	$ 51,350

Notes Payable - Convertible S_2

Notes Payable - Convertible Senior Notes - Additional Information (Details) - 2.25% Convertible Senior Notes due 2022 - Convertible Senior Notes - USD ($) $ in Millions	1 Months Ended
	Jun. 30, 2015	Dec. 31, 2021	Jun. 30, 2019
Notes Payable
Debt issuance costs incurred	$ 11.7
Debt issuance costs allocated to equity components	4
Debt issuance costs allocated to liability components	$ 7.7
Debt instrument term	7 years
Effective interest rate on liability components		10.10%	9.34%

Notes Payable - Convertible S_3

Notes Payable - Convertible Senior Notes - Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest Expense
Contractual interest expense	$ 7,216	$ 7,216	$ 7,361
Amortization of debt issuance costs	1,678	1,462	1,190
Amortization of debt discount	22,256	20,800	17,683
Total interest expense	$ 31,150	$ 29,478	$ 26,234

Notes Payable - Convertible S_4

Notes Payable - Convertible Senior Notes - Future Minimum Payments - Tabular Disclosure (Details) $ in Thousands	Dec. 31, 2021USD ($)
Future minimum payments of Convertible senior notes
2022	$ 126,557
2023	4,500
2024	203,750
2025	3,000
2026	201,500
Total future minimum payments under the convertible senior notes	539,307
Less: amounts representing interest	(18,608)
Less: unamortized debt discount	(61,641)
Less: unamortized debt issuance costs	(4,867)
Net carrying amount	$ 454,191

Notes Payable - Convertible S_5

Notes Payable - Convertible Senior Notes - Future Minimum Payments - Additional Information (Details) $ in Millions	Dec. 31, 2021USD ($)
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes
Notes Payable
Long-term debt, current maturities	$ 120.7

Notes Payable - Convertible S_6

Notes Payable - Convertible Senior Notes Due 2024 and Convertible Senior Notes Due 2026 (Details)	Aug. 12, 2019	Aug. 07, 2019USD ($)$ / shares	Apr. 15, 2019USD ($)$ / sharesshares	Aug. 31, 2019USD ($)D	Jun. 30, 2015USD ($)$ / sharesshares	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Sep. 16, 2019
Notes Payable
Payments for convertible note hedges				$ 25,200,000	$ 21,100,000
Repurchase price				100.00%
Percentage of aggregate principal amount of notes outstanding and payable in case of event of default under the agreement				25.00%
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued					335,700,000	$ 120,699,000	$ 120,699,000
Net proceed received					324,000,000
Fees and expenses					$ 11,700,000
Stated interest rate (as a percent)					2.25%			2.25%
Conversion rate, number of shares to be issued per			68.9172		60.3209
Principal amount used for debt instrument conversion ratio			$ 1,000		$ 1,000
Initial conversion price (in dollars per share) | $ / shares			$ 14.51		$ 16.58
Shares issuable upon conversion of debt (in shares) | shares			23,135,435		20,249,665
Repurchase price, as percentage of principal amount, if company undergoes change of control					100.00%
Amortization period					7 years
Debt instrument term					7 years
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes | Minimum
Notes Payable
Percentage of aggregate principal amount payable, in case of event of default					25.00%
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes
Notes Payable
Net proceed received				$ 391,000,000
Fees and expenses				9,000,000
Conversion rate, number of shares to be issued per	74.6687
Principal amount used for debt instrument conversion ratio		$ 1,000		$ 1,000
Initial conversion price (in dollars per share) | $ / shares		$ 13.39
Number of consecutive trading days before five business days during the measurement period | D				5
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes | Calendar quarter commencing after December 31, 2019
Notes Payable
Number of trading days | D				20
Consecutive trading days | D				30
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes | Measurement period
Notes Payable
Number of business days immediately after any five consecutive trading day period during the measurement period | D				5
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes | Minimum | Calendar quarter commencing after December 31, 2019
Notes Payable
Minimum percentage of stock price				130.00%
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes | Maximum | Measurement period
Notes Payable
Conversion premium percentage on sale price of common stock				98.00%
0.75% Convertible Senior Notes due 2024 | Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued				$ 200,000,000		200,000,000	200,000,000
Stated interest rate (as a percent)	0.75%
Amortization period				5 years
Debt instrument term				5 years
1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued				$ 200,000,000		$ 200,000,000	$ 200,000,000
Stated interest rate (as a percent)	1.50%
Amortization period				7 years
Debt instrument term				7 years

Notes Payable - Convertible S_7

Notes Payable - Convertible Senior Notes Due 2022, Convertible Senior Notes Due 2024 and Convertible Senior Notes Due 2026 (Details) - Convertible Senior Notes - USD ($) $ in Millions	1 Months Ended
	Aug. 31, 2019	Jun. 30, 2015	Dec. 31, 2021	Jun. 30, 2019
2.25% Convertible Senior Notes due 2022
Notes Payable
Debt issuance costs incurred		$ 11.7
Debt issuance costs allocated to equity components		4
Debt issuance costs allocated to liability components		$ 7.7
Debt instrument term		7 years
Effective interest rate on liability components			10.10%	9.34%
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026
Notes Payable
Debt issuance costs incurred	$ 9
Debt issuance costs allocated to equity components	2.1
Debt issuance costs allocated to liability components	$ 6.9
0.75% Convertible Senior Notes due 2024
Notes Payable
Debt instrument term	5 years
Effective interest rate on liability components			6.50%
1.50% Convertible Senior Notes due 2026
Notes Payable
Debt instrument term	7 years
Effective interest rate on liability components			6.80%

Notes Payable - Convertible Not

Notes Payable - Convertible Note Hedge and Warrant Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2021	Dec. 31, 2020	Apr. 15, 2019
Notes Payable
Long-term asset			$ 13,065
Long-term liability			$ 12,088
Net derivative issuance cost	$ 21,100
Convertible Note Hedge
Notes Payable
Shares issuable upon conversion of debt (in shares)		20,249,665
Conversion price (in dollars per share)		$ 16.58		$ 14.51
Long-term asset	91,900
Note Hedge Warrant Derivatives
Notes Payable
Shares into which warrants may be converted (in shares)		20,249,665
Trading day period		150 days
Long-term liability	$ 70,800
Note Hedge Warrants
Notes Payable
Warrants strike price (in dollars per share)		$ 21.50		$ 18.82

Notes Payable - Capped Calls wi

Notes Payable - Capped Calls with Respect to 2024 Convertible Notes and 2026 Convertible Notes (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2019USD ($)$ / shares$ / itemshares	Dec. 31, 2019USD ($)
Capped Calls
Purchase of capped calls		$ 25,159
Equity component of issuance costs for convertible senior notes		$ 2,092
Capped Calls with Respect to 2024 Convertible Notes and 2026 Convertible Notes
Capped Calls
Payment made to enter into Capped Calls	$ 25,200
Strike price (in dollars per share) | $ / shares	$ 13.39
Cap price | $ / item	17.05
Number of shares covered by capped calls (in shares) | shares	29,867,480
Purchase of capped calls	$ 25,000
Equity component of issuance costs for convertible senior notes	$ 200

Commitments and Contingencies -

Commitments and Contingencies - Guarantees (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Indemnification Agreement
Guarantees
Liabilities recorded	$ 0	$ 0

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock (Details)	12 Months Ended
	Dec. 31, 2021Vote
Common stock
Number of voting rights per share	1
Description of the number of voting rights per share	Class A Common Stock is entitled to one vote per share.

Stockholders' Equity - Stock Re

Stockholders' Equity - Stock Repurchase Program (Details) - USD ($) $ in Thousands, shares in Millions	1 Months Ended	12 Months Ended
	May 31, 2021	Dec. 31, 2021
Stock Repurchase Program
Stock repurchase program, authorized amount	$ 150,000
Stock repurchase program, expiration date	Dec. 31, 2022
Common stock repurchased and retired (in shares)		2.4
Common stock repurchased and retired		$ 27,139
Stock repurchase program, remaining authorized repurchase amount		$ 122,900

Employee Stock Benefit Plans -

Employee Stock Benefit Plans - Summary of Expense Recognized by Share-based Compensation Arrangement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	$ 22,281	$ 31,175	$ 31,278
Employee stock options
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	3,154	7,680	12,526
Time-based Restricted Stock Units
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	14,539	18,624	15,488
Performance-based Restricted Stock Units
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	1,295	2,190
Restricted Stock
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	2,684	1,886	2,095
Employee Stock
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	419	722	1,115
Stock awards
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	$ 190	$ 73	$ 54

Employee Stock Benefit Plans _2

Employee Stock Benefit Plans - Share-based Compensation Reflected in the Consolidated Statement of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Stock Benefit Plans
Share-based compensation expense	$ 22,281	$ 31,175	$ 31,278
Research and development
Employee Stock Benefit Plans
Share-based compensation expense	4,849	5,569	6,343
Selling, general and administrative
Employee Stock Benefit Plans
Share-based compensation expense	17,323	23,825	24,281
Restructuring expenses
Employee Stock Benefit Plans
Share-based compensation expense	$ 109	$ 1,781	$ 654

Employee Stock Benefit Plans _3

Employee Stock Benefit Plans - Separation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Stock Benefit Plans
Share-based compensation expense	$ 22,281	$ 31,175	$ 31,278
Employee Stock
Employee Stock Benefit Plans
Share-based compensation expense	$ 419	$ 722	1,115
Spin-off | Share-based Payment Awards, Excluding Employee Stock Purchase Plan
Employee Stock Benefit Plans
Share-based compensation expense			0
Spin-off | Employee Stock
Employee Stock Benefit Plans
Share-based compensation expense			$ 300

Employee Stock Benefit Plans _4

Employee Stock Benefit Plans - Stock Benefit Plans (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2010
2010 Plan | Employee Stock
Stock Benefit Plans
Purchase price as a percentage of fair market value of a share of common stock on the first or last day of an offering period (as a percent)		85.00%
Offering period		6 months
Shares reserved for issuance (in shares)		400,000
Threshold number of additional shares available for future grant (in shares)	1,000,000
Shares available for future grant (in shares)	4,571,500
2010 Plan | Employee Stock | Class A common stock
Stock Benefit Plans
Percentage for the threshold number of additional shares available for future grant, expressed as percentage of common stock outstanding on the last day of the immediately preceding fiscal year (as a percent)	1.00%
2019 Equity plan
Stock Benefit Plans
Shares available for future grant (in shares)	8,773,291
2019 Equity plan | Class A common stock
Stock Benefit Plans
Shares reserved for issuance (in shares)	10,000,000
2005 Equity Plan
Stock Benefit Plans
Shares available for future grant (in shares)	0
2019 Equity Plan and 2010 Purchase Plan
Stock Benefit Plans
Shares available for future grant (in shares)	13,344,791

Employee Stock Benefit Plans _5

Employee Stock Benefit Plans - Restricted Stock Awards - Activity (Details) - Restricted Stock - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Shares
Outstanding at the beginning of the period (in shares)	246,500
Granted (in shares)	230,160
Vested and released (in shares)	(213,400)
Outstanding at the end of the period (in shares)	263,260	246,500
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 10.38
Granted (in dollars per share)	11.67	$ 10.16	$ 10.96
Vested and released (in dollars per share)	11.58
Outstanding at the end of the period (in dollars per share)	$ 11.61	$ 10.38

Employee Stock Benefit Plans _6

Employee Stock Benefit Plans - Restricted Stock Awards - Weighted-average Grant Date Fair Value (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Stock
Weighted-Average Grant Date Fair Value
Weighted-average grant date fair value (in dollars per share)	$ 11.67	$ 10.16	$ 10.96

Employee Stock Benefit Plans _7

Employee Stock Benefit Plans - Restricted Stock Units (Details)	12 Months Ended
	Dec. 31, 2019shares
Restricted Stock Units
Stock Benefit Plans
Right to number of shares of common stock per RSU (in shares)	1

Employee Stock Benefit Plans _8

Employee Stock Benefit Plans - Time-based RSUs - Vesting (Details) - Time-based Restricted Stock Units	12 Months Ended
	Dec. 31, 2021
Minimum
Stock Benefit Plans
Vesting period	2 years
Maximum
Stock Benefit Plans
Vesting period	4 years

Employee Stock Benefit Plans _9

Employee Stock Benefit Plans - Time-based RSUs - Activity (Details) - Time-based Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Shares
Outstanding at the beginning of the period (in shares)	4,170,626
Granted (in shares)	2,707,427
Vested and released (in shares)	(1,697,745)
Forfeited (in shares)	(1,316,200)
Outstanding at the end of the period (in shares)	3,864,108	4,170,626
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 11.90
Granted (in dollars per share)	10.40	$ 11.59	$ 12.11
Vested and released (in dollars per share)	12.18
Forfeited (in dollars per share)	11.38
Outstanding at the end of the period (in dollars per share)	$ 10.89	$ 11.90

Employee Stock Benefit Plans_10

Employee Stock Benefit Plans - Time-based RSUs - Weighted-average Grant Date Fair Value (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Time-based Restricted Stock Units
Weighted-Average Grant Date Fair Value
Weighted-average grant date fair value (in dollars per share)	$ 10.40	$ 11.59	$ 12.11

Employee Stock Benefit Plans_11

Employee Stock Benefit Plans - Performance-based RSUs - Vesting (Details) - Performance-based Restricted Stock Units	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement, Tranche One
Stock Benefit Plans
Vesting period	2 years
Share-based Payment Arrangement, Tranche Two
Stock Benefit Plans
Vesting period	3 years

Employee Stock Benefit Plans_12

Employee Stock Benefit Plans - Performance-based RSUs - Assumptions (Details) - Performance-based Restricted Stock Units	12 Months Ended
	Dec. 31, 2021$ / shares
Weighted-average assumptions used to estimate fair value
Fair value of common stock (in dollars per share)	$ 11.39
Expected volatility (as a percent)	47.90%
Expected term	2 years 7 months 6 days
Risk-free interest rate (as a percent)	0.30%
Expected dividend yield (as a percent)	0.00%

Employee Stock Benefit Plans_13

Employee Stock Benefit Plans - Performance-based RSUs - Activity (Details) - Performance-based Restricted Stock Units	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Number of Shares
Outstanding at the beginning of the period (in shares) | shares	586,157
Granted (in shares) | shares	661,651
Forfeited (in shares) | shares	(414,522)
Outstanding at the end of the period (in shares) | shares	833,286
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 12.48
Granted (in dollars per share) | $ / shares	14.65
Forfeited (in dollars per share) | $ / shares	12.76
Outstanding at the end of the period (in dollars per share) | $ / shares	$ 14.06

Employee Stock Benefit Plans_14

Employee Stock Benefit Plans - Performance-based RSUs - Weighted-average Grant Date Fair Value (Details)	12 Months Ended
	Dec. 31, 2021$ / shares
Performance-based Restricted Stock Units
Weighted-Average Grant Date Fair Value
Weighted-average grant date fair value (in dollars per share)	$ 14.65

Employee Stock Benefit Plans_15

Employee Stock Benefit Plans - Stock Options - General Information (Details)	12 Months Ended
	Dec. 31, 2021
Stock Benefit Plans
Expiration period	10 years
Employee stock options
Stock Benefit Plans
Vesting period	4 years

Employee Stock Benefit Plans_16

Employee Stock Benefit Plans - Stock Options - Assumptions (Details) - Employee stock options	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Weighted-average assumptions used to estimate fair value
Expected volatility (as a percent)		46.60%	46.30%
Expected term		6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate (as a percent)		1.50%	2.50%
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%

Employee Stock Benefit Plans_17

Employee Stock Benefit Plans - Stock Options - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock Benefit Plans
Weighted average grant date fair value (in dollars per share)		$ 5.89	$ 6.10
Share-based compensation expense	$ 22,281	$ 31,175	$ 31,278
Employee stock options
Stock Benefit Plans
Share-based compensation expense	$ 3,154	$ 7,680	$ 12,526
Performance-based milestone options
Stock Benefit Plans
Vested (in shares)	0	0	0

Employee Stock Benefit Plans_18

Employee Stock Benefit Plans - Stock Options - Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Outstanding at the beginning of the period (in shares)	13,459,671
Exercised (in shares)	(1,698,362)
Cancelled (in shares)	(2,388,515)
Outstanding at the end of the period (in shares)	9,372,794	13,459,671
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 12.25
Exercised (in dollars per share)	10.83
Cancelled (in dollars per share)	13.07
Outstanding at the end of the period (in dollars per share)	$ 12.30	$ 12.25
Vested or expected to vest
Number of Shares (in shares)	9,331,488
Weighted-Average Exercise Price (in dollars per share)	$ 12.31
Weighted Average Contractual Life	3 years 5 months 26 days
Aggregate Intrinsic Value	$ 4,509
Stock options
Weighted Average Contractual Life - Outstanding	3 years 6 months 3 days	4 years 3 months 7 days
Aggregate Intrinsic Value - Outstanding	$ 4,528	$ 5,613
Number of Shares - Exercisable (in shares)	8,972,651
Weighted-Average Exercise Price - Exercisable (in dollars per share)	$ 12.33
Weighted Average Contractual Life - Exercisable	3 years 4 months 17 days
Aggregate Intrinsic Value - Exercisable	$ 4,385

Employee Stock Benefit Plans_19

Employee Stock Benefit Plans - Stock Options - Total Intrinsic Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock options
Total intrinsic value of options exercised	$ 2.7	$ 3.5	$ 5.1

Employee Stock Benefit Plans_20

Employee Stock Benefit Plans - Unrecognized Share-based Compensation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Stock options with time-based vesting
Unrecognized share-based compensation
Unrecognized expense, net of estimated forfeitures, options	$ 1,541
Weighted-average remaining recognition period	1 year 1 month 20 days
Restricted Stock
Unrecognized share-based compensation
Unrecognized expense, net of estimated forfeitures, other than options	$ 1,464
Weighted-average remaining recognition period	7 months 6 days
Time-based Restricted Stock Units
Unrecognized share-based compensation
Unrecognized expense, net of estimated forfeitures, other than options	$ 22,545
Weighted-average remaining recognition period	2 years 5 months 15 days
Performance-based Restricted Stock Units
Unrecognized share-based compensation
Unrecognized expense, net of estimated forfeitures, other than options	$ 3,816
Weighted-average remaining recognition period	1 year 8 months 26 days

Income Taxes - Provision for (B

Income Taxes - Provision for (Benefit from) Income Taxes - Tabular Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Current:
State	$ 5,503	$ 2,685
Total current	5,503	2,685
Deferred Federal, State and Local, Tax Expense (Benefit) [Abstract]
Federal	(251,367)
State	(81,927)
Total deferred	(333,294)
Total income tax (benefit) expense	$ (327,791)	$ 2,685

Income Taxes - Provision for _2

Income Taxes - Provision for (Benefit from) Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Taxes
Income tax (benefit) expense	$ (327,791)	$ 2,685
Current:
State	$ 5,503	2,685
Federal Income Tax Expense (Benefit)
Income tax expense related to federal income tax		0	$ 0
State Income Tax Expense (Benefit)
Income tax expense related to state income tax		$ 2,700	0
Foreign Income Tax Expense (Benefit)
Income tax expense related to foreign income tax			$ 0

Income Taxes - Federal Statutor

Income Taxes - Federal Statutory Rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Percent
Federal statutory rate (as a percent)	21.00%	21.00%	21.00%

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of income taxes
Income tax expense (benefit) using U.S. federal statutory rate	$ 42,138	$ 22,861	$ 4,517
Permanent differences	34	74	65
State income taxes, net of federal benefit	12,554	7,565	(1,902)
Disallowed separation related costs			4,658
Executive compensation - Section 162(m)	695	1,718	662
Meals and entertainment	349	395	495
Non-deductible share-based compensation	43	(144)	(1,202)
Excess tax benefits	6,270	5,132	3,324
Fair market valuation of Note Hedge Warrants and Convertible Note Hedges	325	1,680	(290)
Tax credits	(9)	(3,149)	(4,374)
Expiring net operating losses and tax credits	491	1,991	3,764
Effect of change in state tax rate on deferred tax assets and deferred tax liabilities	123	(208)	(2,563)
Change in the valuation allowance	(390,804)	(35,230)	$ (7,154)
Total income tax (benefit) expense	$ (327,791)	$ 2,685

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 165,022	$ 234,772
Tax credit carryforwards	60,125	60,607
Capitalized research and development	4,981	7,498
Share-based compensation	16,857	21,848
Basis difference on collaboration agreement for North America with AbbVie	78,194	62,629
Accruals and reserves	5,003	6,114
Basis difference on 2022 Convertible Notes	8,166	6,183
Intangible assets	5,396
Interest expense		3,386
Operating lease liability	5,971	6,504
Other	3,997	5,049
Total deferred tax assets	353,712	414,590
Deferred tax liabilities:
Basis Difference on 2024 Convertible Notes	(4,363)	(5,951)
Basis Difference on 2026 Convertible Notes	(7,597)	(9,022)
Operating lease right-of-use assets	(4,248)	(4,603)
Total deferred tax liabilities	(16,208)	(19,576)
Net deferred tax assets	337,504	395,014
Valuation allowance	(4,210)	(395,014)
Net deferred tax asset	$ 333,294	$ 0

Income Taxes - Valuation Allowa

Income Taxes - Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Taxes
Net deferred tax assets	$ 337,504	$ 395,014
(Decrease) increase in valuation allowance	(390,800)	$ (35,200)
Release of Valuation Allowance on Majority of Tax Attributes and Other Deferred Tax Assets
Income Taxes
(Decrease) increase in valuation allowance	$ 333,300

Income Taxes - Net Operating Lo

Income Taxes - Net Operating Loss Carryforwards (Details) $ in Millions	Dec. 31, 2021USD ($)
Domestic Tax Authority
Net operating loss carryforwards
Net operating loss carryforwards	$ 935.4
Net operating loss carryforwards, subject to expiration	805.8
Net operating loss carryforwards, indefinite	129.6
State
Net operating loss carryforwards
Net operating loss carryforwards	$ 718.9

Income Taxes - Tax Credit Carry

Income Taxes - Tax Credit Carryforwards (Details) $ in Millions	Dec. 31, 2021USD ($)
Tax credit carryforward
Tax credit carryforward	$ 64.7

Income Taxes - Unrecognized Inc

Income Taxes - Unrecognized Income Tax Benefits - Tabular Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized income tax benefits
Unrecognized Tax Benefits, Beginning Balance	$ 68,087	$ 53,099	$ 38,551
Increases based on tax positions related to the current period	83,206	66,687	51,699
Increases for tax positions of prior periods			1,400
Decreases for tax positions in prior periods	(66,687)	(51,699)	(38,551)
Unrecognized Tax Benefits, End Balance	$ 84,606	$ 68,087	$ 53,099

Income Taxes - Unrecognized I_2

Income Taxes - Unrecognized Income Tax Benefits - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unrecognized tax benefits
Unrecognized tax benefits	$ 84,606	$ 68,087	$ 53,099	$ 38,551
Amount of unrecognized tax benefits that, if recognized, would affect effective tax rate	1,400
Reserve for uncertain tax positions recorded in other liabilities	$ 2,900

Defined Contribution Plan (Deta

Defined Contribution Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plan
Matching contribution, percentage of employee contribution (as a percent)		75.00%	75.00%
Matching contribution, annual employee contribution limit, amount		$ 6,000	$ 6,000
Compensation cost	$ 2,200,000	$ 1,800,000	$ 2,200,000
Minimum
Defined Contribution Plan
Employee contribution per calendar year (as a percent of compensation)	1.00%
Maximum
Defined Contribution Plan
Employee contribution per calendar year (as a percent of compensation)	100.00%
Ironwood Pharmaceuticals, Inc 401(k) Savings Plan, Matching Contributions, 100 Percent on First 3 Percent and 50 Percent on Next 3 Percent, 100 Percent on First 3 Percent
Defined Contribution Plan
Matching contribution, percent of match (as a percent)	100.00%
Matching contribution, percent of employees' gross pay (as a percent)	3.00%
Ironwood Pharmaceuticals, Inc 401(k) Savings Plan, Matching Contributions, 100 Percent on First 3 Percent and 50 Percent on Next 3 Percent, 50 Percent on Next 3 Percent
Defined Contribution Plan
Matching contribution, percent of match (as a percent)	50.00%
Matching contribution, percent of employees' gross pay (as a percent)	3.00%
Ironwood Pharmaceuticals, Inc 401(k) Savings Plan, Matching Contributions, 75 Percent on First $10,000, up to $7,500
Defined Contribution Plan
Matching contribution, percentage of employee contribution (as a percent)	75.00%
Matching contribution, annual employee eligible contribution limit, amount	$ 10,000
Matching contribution, annual employee contribution limit, amount	$ 7,500

Workforce Reduction and Restr_3

Workforce Reduction and Restructuring - Restructuring Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Expenses
Charges	$ 1,073	$ 15,400	$ 3,600

Workforce Reduction and Restr_4

Workforce Reduction and Restructuring - General Information (Details) $ in Millions	1 Months Ended			12 Months Ended
	Sep. 30, 2020employee	Feb. 28, 2019employee	Aug. 31, 2018employee	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Reduction in Workforce, Termination of Lesinurad License Agreement, August 16, 2018
Workforce Reduction
Number of employees expected to be eliminated | employee			100
Reduction in Workforce, February 7, 2019
Workforce Reduction
Number of employees expected to be eliminated | employee		35
Restructuring Expenses
Employee severance, benefits and related costs | $					$ 3.7
Reduction in Workforce, Discontinued Development of IW-3718, September 29, 2020
Workforce Reduction
Number of employees expected to be eliminated | employee	100
Restructuring Expenses
Restructuring expenses and impairment of certain fixed assets | $				$ 15.5
Impairment of Long-Lived Assets
Impairment of long-lived assets | $				$ 1.2

Workforce Reduction and Restr_5

Workforce Reduction and Restructuring - Tabular Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Workforce Reduction
Balance at beginning of period	$ 10,907
Charges	1,073	$ 15,400	$ 3,600
Amounts paid	(10,664)
Adjustments	(854)
Balance at end of period	462	10,907
Employee severance, benefits and related costs
Workforce Reduction
Balance at beginning of period	10,902	75
Charges	1,025	11,563
Amounts paid	(10,611)	(736)
Adjustments	(854)
Balance at end of period	462	10,902	75
Employee severance, benefits and related costs | Reduction in Workforce, February 7, 2019
Workforce Reduction
Balance at beginning of period	0	75
Amounts paid		(75)
Balance at end of period		0	75
Employee severance, benefits and related costs | Reduction in Workforce, Discontinued Development of IW-3718, September 29, 2020
Workforce Reduction
Balance at beginning of period	10,902	0
Charges		11,563
Amounts paid		(661)
Balance at end of period		10,902	0
Contract related costs
Workforce Reduction
Balance at beginning of period	5	104
Charges	48	108
Amounts paid	(53)	(103)
Adjustments		(104)
Balance at end of period	0	5	104
Contract related costs | Reduction in Workforce, Termination of Lesinurad License Agreement, August 16, 2018
Workforce Reduction
Balance at beginning of period	0	104
Adjustments		(104)
Balance at end of period		0	104
Contract related costs | Reduction in Workforce, Discontinued Development of IW-3718, September 29, 2020
Workforce Reduction
Balance at beginning of period	$ 5	0
Charges		108
Amounts paid		(103)
Balance at end of period		$ 5	$ 0

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Selected Quarterly Financial Data
Total revenues	$ 117,130	$ 103,747	$ 104,031	$ 88,845	$ 116,680	$ 103,468	$ 89,432	$ 79,943	$ 413,753	$ 389,523	$ 428,413
Total cost and expenses	60,538	38,576	38,933	43,447	65,296	57,852	56,719	66,716	181,494	246,583	308,290
Other expense, net	(10,337)	(5,499)	(10,726)	(5,040)	(6,884)	(9,804)	(7,509)	(9,882)	(31,602)	(34,079)	(61,180)
Net income	41,374	55,845	391,303	39,926	43,204	34,423	25,204	3,345	528,448	106,176	21,505
Comprehensive income	$ 41,374	$ 55,845	$ 391,303	$ 39,926	$ 43,204	$ 34,423	$ 25,204	$ 3,345	$ 528,448	$ 106,176	$ 21,505
Net income per share - basic (in dollars per share)	$ 0.25	$ 0.34	$ 2.42	$ 0.25	$ 0.27	$ 0.22	$ 0.16	$ 0.02	$ 3.26	$ 0.67	$ 0.14
Net income per share - diluted (in dollars per share)	$ 0.25	$ 0.34	$ 2.39	$ 0.25	$ 0.27	$ 0.21	$ 0.16	$ 0.02	$ 3.21	$ 0.66	$ 0.14

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	2 Months Ended	12 Months Ended
	Feb. 15, 2022	Dec. 31, 2021
Subsequent Event
Common stock repurchased and retired (in shares)		2.4
Common stock repurchased and retired		$ 27,139
Subsequent Event
Subsequent Event
Common stock repurchased and retired (in shares)	4.5
Common stock repurchased and retired, weighted-average price (in dollars per share)	$ 11.27
Common stock repurchased and retired	$ 50,700