Ironwood Pharmaceuticals (IRWD) 10-Q 5 May 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - $ / shares	3 Months Ended
	Mar. 31, 2022	Apr. 30, 2022
Cover [Abstract]
Entity Central Index Key	0001446847
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		153,837,866
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 593,371	$ 620,129
Accounts receivable, net	105,515	114,042
Prepaid expenses and other current assets	8,537	8,689
Restricted cash	1,250	1,250
Convertible note hedges	1,428	1,115
Total current assets	710,101	745,225
Restricted cash, net of current portion	485	485
Accounts receivable, net of current portion	14,143	23,998
Property and equipment, net	7,229	7,575
Operating lease right-of-use assets	15,028	15,350
Deferred tax assets	335,440	333,294
Other assets	955	1,000
Total assets	1,083,381	1,126,927
Current liabilities:
Accounts payable	532	935
Accrued research and development costs	5,442	15,896
Accrued expenses and other current liabilities	16,852	23,566
Current portion of operating lease liabilities	3,097	3,127
Current portion of convertible senior notes	120,581	116,858
Note hedge warrants	899	1,316
Total current liabilities	147,403	161,698
Convertible senior notes, net of current portion	395,053	337,333
Operating lease obligations, net of current portion	18,031	18,484
Other liabilities	5,111	3,501
Commitments and contingencies
Stockholders' equity:
Class A Common Stock, $0.001 par value, 500,000,000 shares authorized and 155,115,155 shares issued and outstanding at March 31, 2022 and 500,000,000 shares authorized and 162,036,461 shares issued and outstanding at December 31, 2021	155	162
Additional paid-in capital	1,350,268	1,543,357
Accumulated deficit	(832,640)	(937,608)
Total stockholders' equity	517,783	605,911
Total liabilities and stockholders' equity	$ 1,083,381	$ 1,126,927

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
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	155,115,155	162,036,461
Common stock, shares outstanding	155,115,155	162,036,461

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Total revenues	$ 97,529	$ 88,845
Operating expenses:
Research and development	10,822	15,484
Selling, general and administrative	28,861	27,652
Restructuring expenses		311
Total operating expenses	39,683	43,447
Income from operations	57,846	45,398
Other (expense) income:
Interest expense	(2,341)	(7,626)
Interest and investment income	230	196
Gain on derivatives	730	2,390
Other expense, net	(1,381)	(5,040)
Income before income taxes	56,465	40,358
Income tax expense	(17,664)	(432)
Net income	38,801	39,926
Comprehensive income	$ 38,801	$ 39,926
Net income per share - basic (in dollars per share)	$ 0.25	$ 0.25
Net income per share - diluted (in dollars per share)	$ 0.21	$ 0.25
Weighted average shares used in computing net income per share - basic (in shares)	157,821	160,967
Weighted average shares used in computing net income per share - diluted (in shares)	189,540	162,347
Collaborative arrangements revenue
Revenues:
Total revenues	$ 97,529	$ 88,665
Sale of active pharmaceutical ingredient
Revenues:
Total revenues		$ 180

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional paid-in capitalCumulative Effect, Period of Adoption, Adjustment	Additional paid-in capital	Accumulated deficitCumulative Effect, Period of Adoption, Adjustment	Accumulated deficit	Cumulative Effect, Period of Adoption, Adjustment	Total
Balance at Dec. 31, 2020	$ 161		$ 1,528,535		$ (1,466,056)		$ 62,640
Balance (in shares) at Dec. 31, 2020	160,616,675
Increase (Decrease) in Stockholders' Equity (Deficit)
Issuance of common stock related to share-based awards and employee stock purchase plan	$ 1		2,229				2,230
Issuance of common stock related to share-based awards and employee stock purchase plan (in shares)	1,314,337
Share-based compensation expense related to share-based awards and employee stock purchase plan			5,396				5,396
Net income					39,926		39,926
Balance at Mar. 31, 2021	$ 162		1,536,160		(1,426,130)		110,192
Balance (in shares) at Mar. 31, 2021	161,931,012
Balance at Dec. 31, 2021	$ 162	$ (110,217)	1,543,357	$ 66,167	(937,608)	$ (44,050)	$ 605,911
Balance (in shares) at Dec. 31, 2021	162,036,461						162,036,461
Increase (Decrease) in Stockholders' Equity (Deficit)
Issuance of common stock related to share-based awards and employee stock purchase plan	$ 1		1,520				$ 1,521
Issuance of common stock related to share-based awards and employee stock purchase plan (in shares)	1,087,966
Share-based compensation expense related to share-based awards and employee stock purchase plan			6,089				6,089
Repurchases of common stock	$ (8)		(90,481)				$ (90,489)
Repurchases of common stock (in shares)	(8,009,272)						(8,000,000)
Net income					38,801		$ 38,801
Balance at Mar. 31, 2022	$ 155		$ 1,350,268		$ (832,640)		$ 517,783
Balance (in shares) at Mar. 31, 2022	155,115,155						155,115,155

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income	$ 38,801	$ 39,926
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	355	410
Loss on disposal of property and equipment		17
Share-based compensation expense	6,089	5,396
Change in fair value of note hedge warrants	(417)	(4,109)
Change in fair value of convertible note hedges	(313)	1,719
Non-cash interest expense	537	5,822
Deferred income taxes	14,708
Changes in assets and liabilities:
Accounts receivable, net	18,382	35,037
Prepaid expenses and other current assets	53	(1,681)
Operating lease right-of-use assets	322	297
Other assets	45	19
Accounts payable and accrued expenses	(7,117)	(7,942)
Accrued research and development costs	(10,454)	(644)
Operating lease liabilities	(483)	(440)
Other liabilities	3,616	(133)
Net cash provided by operating activities	64,124	73,694
Cash flows from investing activities:
Purchases of property and equipment	(9)
Net cash (used in) investing activities	(9)
Cash flows from financing activities:
Proceeds from exercise of stock options and employee stock purchase plan	1,622	2,211
Repurchases of common stock	(92,495)
Net cash provided by (used in) financing activities	(90,873)	2,211
Net increase in cash, cash equivalents and restricted cash	(26,758)	75,905
Cash, cash equivalents and restricted cash, beginning of period	621,864	364,784
Cash, cash equivalents and restricted cash, end of period	$ 595,106	$ 440,689

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Reconciliation of cash, cash equivalents, and restricted cash to the condensed consolidated balance sheets
Cash and cash equivalents	$ 593,371	$ 620,129	$ 438,469
Restricted cash	1,735		2,220
Total cash, cash equivalents, and restricted cash	$ 595,106	$ 621,864	$ 440,689	$ 364,784

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2022
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 (“GC-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 ® to adult men and women suffering from IBS-C or CIC in Canada, and to adult men and women suffering from IBS-C in certain European countries. ​ 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 AbbVie AbbVie ​ Outside of the U.S., the Company earns royalties as a percentage of net sales of products containing linaclotide as an active ingredient by the Company’s collaboration partners. AbbVie 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 AbbVie ​ The Company has 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. ​ The Company is also advancing IW-3300, GC-C agonist, for the potential treatment of visceral pain conditions, including interstitial cystitis/bladder pain syndrome (IC/BPS) and endometriosis. ​ 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	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies ​ Basis of Presentation ​ The accompanying condensed consolidated financial statements and the related disclosures are unaudited and have been prepared in accordance with accounting principles generally accepted in the U.S. Additionally, certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, which was filed with the Securities and Exchange Commission on February 18, 2022 (the “2021 Annual Report on Form 10-K”). ​ The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all normal recurring adjustments considered necessary for a fair statement of the Company’s financial position as of March 31, 2022, and the results of its operations for the three months ended March 31, 2022 and 2021, its statements of stockholders’ equity for the three months ended March 31, 2022 and 2021, and its cash flows for the three months ended March 31, 2022 and 2021. The results of operations for the three months ended March 31, 2022 and 2021 are not necessarily indicative of the results that may be expected for the full year or any other subsequent interim period. ​ Principles of Consolidation ​ The accompanying condensed consolidated financial statements include the accounts of Ironwood and its wholly-owned subsidiaries as of March 31, 2022, Ironwood Pharmaceuticals Securities Corporation and Ironwood Pharmaceuticals GmbH. All intercompany transactions and balances are eliminated in consolidation. ​ Use of Estimates ​ The preparation of condensed 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 condensed 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 condensed 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. Reclassifications ​ ​ Summary of Significant Accounting Policies ​ The Company’s significant accounting policies are described in Note 2, Summary of Significant Accounting Policies ​ 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 three months ended March 31, 2022 that had a material effect on its condensed consolidated financial statements. ​ 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 ​ The Company adopted ASU 2020-06 on January 1, 2022 using the modified retrospective approach, which resulted in a cumulative-effect adjustment ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ Effect of the Adoption ​ January 1, 2022 Consolidated Balance Sheet As Reported of ASU 2020-06 As Adjusted Deferred tax assets ​ $ 333,294 ​ $ 16,855 ​ $ 350,149 Current portion of convertible senior notes ​ ​ 116,858 ​ ​ 3,581 ​ ​ 120,439 Long-term portion of convertible senior notes ​ ​ 337,333 ​ ​ 57,324 ​ ​ 394,657 Additional paid-in-capital ​ ​ 1,543,357 ​ ​ (110,217) ​ ​ 1,433,140 Retained earnings ​ ​ (937,608) ​ ​ 66,167 ​ ​ (871,441) ​ Interest expense recognized in future periods is expected to be reduced as a result of accounting for convertible debt instruments as a single liability measured at amortized cost, with an expected decrease of $22.1 million of non-cash interest expense during the year ended December 31, 2022 compared to the year ended December 31, 2021 related to convertible debt instruments outstanding on the adoption date. ​ The adoption of ASU 2020-06 does not impact the Company’s liquidity or cash flows. ​ 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 (“ASU 2021-04”). The guidance in ASU 2021-04 clarifies and reduces diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options that remain equity classified after modification or exchange. The standard is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. The Company adopted ASU 2021-04 as of January 1, 2022 . The adoption of ASU 2021-04 did not have a material impact on the Company’s financial position and results of operations. ​ 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 condensed consolidated financial statements upon future adoption. ​

Net Income Per Share

Net Income Per Share	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Net Income Per Share	3. 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ ​ 2022 2021 ​ Numerator: ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 38,801 ​ $ 39,926 ​ Add back interest expense, net of tax benefit, on assumed conversion of 2024 Convertible Notes ​ ​ 444 ​ ​ — ​ Add back interest expense, net of tax benefit, on assumed conversion of 2026 Convertible Notes ​ ​ 666 ​ ​ — ​ Numerator used in computing net income per share — diluted ​ ​ 39,911 ​ ​ 39,926 ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — basic ​ ​ 157,821 ​ ​ 160,967 ​ Effect of dilutive securities: ​ ​ ​ ​ ​ ​ ​ Stock options ​ ​ 324 ​ ​ 268 ​ Time-based restricted stock units ​ ​ 1,132 ​ ​ 957 ​ Performance-based restricted stock units ​ ​ 222 ​ ​ 13 ​ Restricted stock ​ ​ 166 ​ ​ 136 ​ Shares subject to issuance under Employee Stock Purchase Plan ​ ​ 7 ​ ​ 6 ​ 2024 Convertible Notes assumed conversion ​ ​ 14,934 ​ ​ — ​ 2026 Convertible Notes assumed conversion ​ ​ 14,934 ​ ​ — ​ Dilutive potential common shares ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — diluted ​ ​ 189,540 ​ ​ 162,347 ​ Net income per share — basic ​ $ 0.25 ​ $ 0.25 ​ Net income per share — diluted ​ $ 0.21 ​ $ 0.25 ​ ​ ​ 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2022 2021 ​ Stock options ​ 6,890 ​ 10,566 ​ Restricted stock awards — ​ 25 ​ Time-based restricted stock units ​ 114 ​ 407 ​ Performance-based restricted stock units ​ 858 ​ 20 ​ Note Hedge Warrants ​ 8,318 ​ 8,318 ​ 2022 Convertible Notes ​ — ​ 8,318 ​ 2024 Convertible Notes ​ — ​ 14,934 ​ 2026 Convertible Notes ​ — ​ 14,934 ​ Total 16,180 57,522 ​ ​ ​ Prior to the adoption of ASU 2020-06, the potentially dilutive impact of the 2022 Convertible Notes, 2024 Convertible Notes and 2026 Convertible notes (together, the “Convertible Senior Notes”) (Note 8) was determined using the treasury stock method. Under this method, no numerator or denominator adjustments arose from the principal and interest components of the Convertible Senior Notes because the Company had the intent and ability to settle the Convertible Senior Notes’ principal and interest in cash. Instead, the Company was 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 was calculated based on whether the average market price of the Company’s Class A Common Stock during the reporting period was in excess of the conversion price of the Convertible Senior Notes. There was no calculated spread added to the denominator for the three months ended March 31, 2021. ​ Following the adoption of ASU 2020-06 on January 1, 2022, the dilutive impact of the Convertible Senior Notes is determined using the if-converted method. Under the if-converted method, the Convertible Senior Notes are assumed to be converted into common stock at the beginning of the period (or at the time of issuance, if later). Interest charges are deducted from the numerator, unless the principal amount of the convertible instruments is required to be paid in cash. ​ There was no dilutive impact of the 2022 Convertible Notes for the three months ended March 31, 2022 because the Company had elected prior to the beginning of the period to settle the conversion of 2022 Convertible Notes, if any, with a combination settlement of a cash payment equal to the principal value of converted notes and shares of Class A Common Stock equal to the conversion value in excess of the principal value, if any (Note 8). Accordingly, interest expense was not removed from the numerator and there was no calculated spread added to the denominator because the average market price of the Company’s Class A common stock during the period was not in excess of the conversion price.

Collaboration, License, and Oth

Collaboration, License, and Other Agreements	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Collaboration, License, and Other Agreements	4. Collaboration, License and Other Agreements ​ For the three months ended March 31, 2022, 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 ® ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ Collaborative Arrangements Revenue ​ 2022 2021 ​ Linaclotide Collaboration and License Agreements: ​ ​ ​ ​ ​ ​ ​ AbbVie (North America) ​ $ 94,901 ​ $ 86,499 ​ AbbVie (Europe and other) ​ ​ 610 ​ ​ 600 ​ AstraZeneca (China, including Hong Kong and Macau) ​ ​ 192 ​ 210 ​ Astellas (Japan) ​ ​ 523 ​ 496 ​ Co-Promotion and Other Agreements: ​ ​ ​ ​ ​ ​ ​ Alnylam (GIVLAARI) ​ ​ 823 ​ ​ 456 ​ Other ​ ​ 480 ​ ​ 404 ​ Total collaborative arrangements revenue ​ $ 97,529 ​ $ 88,665 ​ Sale of API Linaclotide Agreements: ​ ​ ​ ​ ​ ​ ​ AstraZeneca (China, including Hong Kong and Macau) ​ $ — ​ $ 21 ​ Other ​ ​ — ​ ​ 159 ​ Total sale of API ​ $ — ​ $ 180 ​ ​ ​ ​ 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 three months ended March 31, 2022 and 2021. ​ 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 March 31, 2022, $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 three months ended March 31, 2022 and 2021, the Company incurred $1.7 million and $1.8 million, respectively, 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 $2.4 million and $2.9 million, in incremental research and development costs during the three months ended March 31, 2022 and 2021, respectively, 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. AbbVie ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2022 2021 Collaborative arrangements revenue related to sales of LINZESS in the U.S. ​ $ 94,319 ​ $ 85,949 ​ Royalty revenue ​ 582 ​ 550 ​ Total collaborative arrangements revenue ​ $ 94,901 ​ $ 86,499 ​ ​ ​ The Company incurred $8.7 million and $7.1 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 an insignificant amount in patent prosecution and patent litigation costs for each of the three months ended March 31, 2022 and 2021. ​ ® ​ License Agreement with AbbVie (All countries other than the countries and territories of North America, China (including Hong Kong and Macau), and Japan) The Company has a license agreement with AbbVie to develop, manufacture and commercialize linaclotide in (i) Europe, and (ii) all countries other than China (including Hong Kong and Macau), Japan, and the countries and territories of North America, or collectively the “Expanded Territory,” for the treatment of IBS-C, CIC and other GI conditions. Under the license agreement, as amended, AbbVie is obligated to pay the Company, (i) royalties based on sales volume in Europe in the upper-teens percent, and (ii) on a country-by-country and product-by-product basis in the Expanded Territory, 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 Europe and 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 license agreement also contains certain sales-based milestones and commercial launch milestones, which could total up to ​ License Agreement for Japan with Astellas The Company has a license agreement with Astellas to develop, manufacture, and commercialize linaclotide for the treatment of IBS-C, CIC and other GI conditions in Japan. Under the license agreement, as amended, 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 as an active ingredient. These royalty payments are subject to reduction following the expiration of certain licensed patents and the occurrence of generic competition in Japan. ​ The Company recognized $0.5 million of royalty revenue during each of the three months ended March 31, 2022 and 2021. ​ Collaboration Agreement for China (including Hong Kong and Macau) with AstraZeneca The Company has a collaboration agreement with AstraZeneca under which AstraZeneca has the exclusive right to develop, manufacture and commercialize products containing linaclotide in the AstraZeneca License Territory. Under the collaboration agreement, AstraZeneca is 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. The Company recognized $0.2 million and $0.1 million of royalty revenue during the three months ended March 31, 2022 and 2021, respectively. The Company is entitled to receive non-contingent payments totaling $35.0 million in three installments through 2024, of which $25.0 million remained outstanding at March 31, 2022. In addition, AstraZeneca may be required to make milestone payments totaling up to $90.0 million contingent on the achievement of certain sales targets. The significant financing component of the transaction was $2.6 million and is recognized as interest income through 2024 using the effective interest method. At March 31, 2022, the current portion and non-current portion of the non-contingent receivable due from AstraZeneca was $10.0 million and $14.1 million, respectively. At December 31, 2021, the non-contingent receivable due from AstraZeneca was $24.0 million and was classified as non-current. ​ 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 to COUR of $6.0 million and agreed to pay a non-contingent payment and milestone payments to COUR totaling $13.5 million in connection with certain development activities and regulatory milestones. After reviewing the data from the clinical study for CNP-104, 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. The Company remains eligible to receive royalties based on a percentage of net sales of GIVLAARI that are directly attributable to the Company’s promotional efforts until September 30, 2022, which is one year following the termination of the agreement. During the three months ended March 31, 2022 and 2021, the Company recognized

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Fair Value of Financial Instruments	5. 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 March 31, 2022 and December 31, 2021 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 ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ March 31, 2022 ​ ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 278,970 ​ ​ $ 278,970 ​ $ — ​ $ — Repurchase agreements ​ ​ 277,001 ​ ​ ​ 277,001 ​ ​ — ​ ​ — Restricted cash: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 1,735 ​ ​ ​ 1,735 ​ ​ — ​ ​ — Convertible note hedges ​ ​ 1,428 ​ ​ ​ — ​ ​ — ​ ​ 1,428 Total assets measured at fair value ​ $ 559,134 ​ ​ $ 557,706 ​ $ — ​ $ 1,428 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Note hedge warrants ​ $ 899 ​ ​ $ — ​ $ — ​ $ 899 Total liabilities measured at fair value ​ $ 899 ​ ​ $ — ​ $ — ​ $ 899 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting Date Using ​ ​ ​ Quoted Prices in Significant Other Significant ​ ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ December 31, 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 ​ There were no transfers between fair value measurement levels during each of the three months ended March 31, 2022 or 2021. ​ 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 March 31, 2022 and December 31, 2021 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 March 31, 2022 and December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ December 31, 2021 ​ ​ ​ Convertible Note Hedge ​ Convertible Note Hedge ​ ​ Note Hedges ​ Warrants Note Hedges ​ Warrants Risk-free interest rate (1) ​ ​ 0.4 % ​ 1.4 % ​ 0.2 % ​ 0.4 % Expected term ​ 0.2 ​ 0.8 ​ ​ 0.5 ​ 1.0 ​ Stock price (2) ​ $ 12.58 ​ $ 12.58 ​ $ 11.66 ​ $ 11.66 ​ Strike price (3) ​ $ 14.51 ​ $ 18.82 ​ $ 14.51 ​ $ 18.82 ​ Common stock volatility (4) ​ ​ 31.9 % ​ 28.9 % ​ 27.0 % ​ 32.2 % 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 quarters ended March 31, 2022 and December 31, 2021, 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 condensed 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, 2021 through March 31, 2022 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible ​ Note Hedge ​ Note Hedges Warrants Balance at December 31, 2021 ​ $ 1,115 ​ $ (1,316) Change in fair value, recorded as a component of gain on derivatives ​ ​ 313 ​ ​ 417 Balance at March 31, 2022 ​ $ 1,428 ​ $ (899) ​ ​ ​ 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. Prior to the adoption of ASU 2020-06, 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 8). Following the adoption of ASU 2020-06 on January 1, 2022, the equity component was eliminated and each of the 2022 Convertible Notes, 2024 Convertible Notes, and 2026 Convertible Notes are measured as a single liability. 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 as of March 31, 2022 and December 31, 2021. The estimated fair value of the 2024 Convertible Notes was $227.8 million and $221.9 million as of March 31, 2022 and December 31, 2021, respectively. The estimated fair value of the 2026 Convertible Notes was $236.5 million and $227.2 million as of March 31, 2022 and December 31, 2021, respectively. Capped Calls with Respect to 2024 Convertible Notes and 2026 Convertible Notes ​ Derivatives and Hedging ​

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities ​ Accrued expenses and other current liabilities consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 December 31, 2021 Accrued compensation and benefits ​ $ 10,086 ​ $ 17,115 Accrued interest ​ ​ 2,105 ​ ​ 301 Stock repurchase ​ 1,002 ​ 3,009 Other ​ ​ 3,659 ​ ​ 3,141 Total accrued expenses and other current liabilities ​ $ 16,852 ​ $ 23,566 As of March 31, 2022, other accrued expenses of $3.7 million included $3.2 million of uninvoiced vendor liabilities and $0.3 million of state income taxes payable. As of December 31, 2021, other accrued expenses of $3.1 million included $2.7 million of uninvoiced vendor liabilities and $0.2 million of state income taxes payable. ​

Leases

Leases	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Leases	7. Leases ​ The Company’s lease portfolio for the three months ended March 31, 2022 includes: an office lease for its current headquarters location, a data center colocation lease, vehicle leases for its salesforce representatives, and leases for computer and office equipment. ​ The Company’s office lease and vehicle lease require letters of credit to secure the Company’s obligations under the lease agreements totaling $1.7 million and are collateralized by money market accounts recorded as restricted cash on the Company’s condensed consolidated balance sheets as of March 31, 2022 and December 31, 2021. ​ Lease cost is recognized on a straight-line basis over the lease term. The components of lease cost for the three months ended March 31, 2022 and 2021 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ ​ 2022 ​ 2021 ​ Operating lease cost ​ $ 628 ​ $ 631 ​ Short-term lease cost ​ ​ 260 ​ ​ 214 ​ Total lease cost ​ $ 888 ​ $ 845 ​ ​ Supplemental information related to leases for the periods reported is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2022 ​ 2021 Cash paid for amounts included in the measurement of lease liabilities (in thousands) ​ $ 789 ​ ​ $ 773 ​ Weighted-average remaining lease term of operating leases (in years) ​ ​ 8.1 ​ ​ ​ 9.0 ​ Weighted-average discount rate of operating leases ​ ​ 5.8 % ​ ​ 5.8 % ​ Future minimum lease payments under non-cancelable operating leases as of March 31, 2022 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 (1) ​ $ 2,340 2023 ​ ​ 3,065 2024 ​ ​ 3,126 2025 ​ ​ 3,189 2026 ​ 3,252 2027 and thereafter ​ 11,603 Total future minimum lease payments ​ ​ 26,575 Less: present value adjustment ​ ​ (5,447) Operating lease liabilities ​ ​ 21,128 Less: current portion of operating lease liabilities ​ ​ (3,097) Operating lease liabilities, net of current portion ​ $ 18,031 (1) For the nine months ending December 31, 2022. ​ Summer Street Lease ​ 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 March 31, 2022, the balances of the right-of-use asset and operating lease liability were $15.0 million and $21.1 million, respectively. 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. ​ Lease costs recorded during each of the three months ended March 31, 2022 and 2021 were $0.6 million. ​

Notes Payable

Notes Payable	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Notes Payable	8. 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, through December 15, 2021, 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, if any, with a combination settlement of a cash payment equal to the principal value of converted notes and shares of Class A Common Stock equal to the conversion value in excess of the principal value, 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. On April 1, 2019, Ironwood completed the separation (the “Separation”) of its soluble guanylate cyclase business, and certain other assets and liabilities, into a separate, independent publicly traded company, Cyclerion Therapeutics, Inc. (“Cyclerion”). The Separation was effected by means of a distribution of all the outstanding shares of common stock, with no par value, of Cyclerion, through a dividend of Cyclerion’s common stock to the Company’s stockholders of record as of the close of business on March 19, 2019. In connection with the Separation, 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. Upon issuance, 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 the date of issuance. The debt discount has been amortized to interest expense using the effective interest method over seven years, or the expected life of the 2022 Convertible Notes. The equity component was not remeasured as long as it continued 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. ​ Upon the adoption of ASU 2020-06 on January 1, 2022, the equity component is no longer bifurcated from the liability component and each debt instrument is accounted for as a single liability measured at amortized cost. Accordingly, the unamortized debt discount as of the adoption date in the amount of $3.5 million was derecognized, resulting in an increase to the current portion of convertible senior notes and a decrease to stockholders’ equity. Additionally, there is no longer non-cash interest expense associated with the amortization of the original issue discount. During the three months ended March 31, 2021, the Company recognized $1.8 million in non-cash interest expense related to the debt discount. ​ 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. ​ Upon issuance, 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 has been amortized to interest expense using the effective interest method over approximately five ​ Upon the adoption of ASU 2020-06 on January 1, 2022, the equity component is no longer bifurcated from the liability component and each debt instrument is accounted for as a single liability measured at amortized cost. Accordingly, the unamortized debt discount as of the adoption date in the amount of $22.3 million and $35.8 million for the 2024 Convertible Notes and 2026 Convertible Notes, respectively, was derecognized, resulting in an increase to the non-current portion of convertible senior notes and a decrease to stockholders’ equity. Additionally, there is no longer non-cash interest expense associated with the amortization of the original issue discount. During the three months ended March 31, 2021, the Company recognized $2.0 million and $1.7 million in non-cash interest expense related to the debt discount for the 2024 Convertible Notes and 2026 Convertible Notes, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ 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) Less: unamortized debt issuance costs ​ ​ (5,065) ​ ​ (4,867) Net carrying amount ​ ​ 515,634 ​ ​ 454,191 Equity component: ​ ​ ​ ​ ​ ​ 2022 Convertible Notes ​ ​ — ​ ​ 19,807 2024 Convertible Notes ​ ​ — ​ ​ 41,152 2026 Convertible Notes ​ ​ — ​ ​ 51,350 Total equity component ​ $ — ​ $ 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. Upon the adoption of ASU 2020-06, the costs originally allocated to the equity component are reflected within the current portion of convertible senior notes and recorded as interest expense over the life of the 2022 Convertible Notes. The Company determined the expected life of the 2022 Convertible Notes was equal to their seven-year term. From the date of the partial repurchase of the 2022 Convertible Notes in August 2019 through March 31, 2022, the effective annual interest rate on the 2022 Convertible Notes was 2.7%. The effective annual interest rate is computed using the contractual interest and the amortization of debt issuance costs. Prior to the adoption of ASU 2020-06, the effective annual interest rate calculation also included the amortization of the original issue discount. 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. Upon the adoption of ASU 2020-06 on January 1, 2022, the costs originally allocated to the equity component are reflected within the current portion of convertible senior notes and recorded as interest expense over the life 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 three months ended March 31, 2022 and 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ 2022 2021 Contractual interest expense ​ $ 1,804 ​ $ 1,804 Amortization of debt issuance costs ​ ​ 537 ​ ​ 398 Amortization of debt discount ​ ​ — ​ ​ 5,424 Total interest expense ​ $ 2,341 ​ $ 7,626 ​ Future minimum payments under the convertible senior notes as of March 31, 2022, are as follows (in thousands): ​ ​ ​ ​ 2022 (1) ​ $ 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 ​ ​ — Less: unamortized debt issuance costs ​ ​ (5,065) Convertible senior notes balance ​ $ 515,634 (1) For the nine months ending December 31, 2022. ​ As of March 31, 2022, $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 condensed 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 5). As of March 31, 2022 and December 31, 2021, the Convertible Note Hedges and Note Hedge Warrants were classified as current assets and current liabilities, respectively, on the Company’s condensed 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.

Employee Stock Benefit Plans

Employee Stock Benefit Plans	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Employee Stock Benefit Plans	9. Employee Stock Benefit Plans ​ The Company has several share-based compensation plans under which stock options, restricted stock awards, restricted stock units 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 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2022 2021 Share-based compensation expense: ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 1,158 ​ $ 1,243 ​ Selling, general and administrative ​ ​ 4,931 ​ 4,043 ​ Restructuring expenses ​ ​ — ​ ​ 110 ​ Total share-based compensation expense included in operating expenses ​ ​ 6,089 ​ ​ 5,396 ​ Income tax expense (benefit) ​ ​ (720) ​ ​ — ​ Total share-based compensation expense, net of tax ​ $ 5,369 ​ $ 5,396 ​ ​

Stock Repurchase Plan

Stock Repurchase Plan	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Share Repurchase Plan	10. Share Repurchase Plan 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.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Income Taxes	11. Income Taxes The income tax provision during interim periods is computed by applying an estimated annual effective income tax rate to year-to-date pre-tax income, plus adjustments for significant unusual or infrequently occurring items, in accordance with ASC 740-270, Income Taxes – Interim Reporting During the three months ended March 31, 2022, the Company recorded income tax expense of $17.7 million. The Company’s provision for income taxes during the three months ended March 31, 2022 increased compared to historical amounts due to the release of the Company’s valuation allowance on the majority of its net operating losses and other deferred tax assets during the second quarter of 2021. Due to the Company's ability to offset its pre-tax income against net operating losses, it expects the majority of its tax provision to represent a non-cash expense until its net operating losses have been fully utilized. For the three months ended March 31, 2021, the Company maintained a full valuation allowance against net deferred tax assets and recorded income tax expense of $0.4 million for certain states which had temporarily disallowed or only partially allow the use of net operating losses to offset taxable income. 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. On a periodic basis, the Company reassesses any valuation allowances that it maintains on its deferred tax assets, weighing positive and negative evidence to assess the recoverability of the deferred tax assets. Until the second quarter of 2021, the Company recorded a full valuation allowance against net deferred tax assets. During the three months ended June 30, 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, the Company determined it was more likely than not that it will realize the majority of its deferred tax assets and during the three months ended June 30, 2021, released the majority of its valuation allowance, as a discrete item, 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.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block
Subsequent Events	12. Subsequent Event ​ Share Repurchases ​ From April 1, 2022 to April 30, 2022, the Company repurchased 1.3 million shares of its common stock at a weighted-average price of $12.14 per share for a total of $15.9 million. ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Policy Text Blocks
Basis of Presentation	Basis of Presentation ​ The accompanying condensed consolidated financial statements and the related disclosures are unaudited and have been prepared in accordance with accounting principles generally accepted in the U.S. Additionally, certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, which was filed with the Securities and Exchange Commission on February 18, 2022 (the “2021 Annual Report on Form 10-K”). ​ The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all normal recurring adjustments considered necessary for a fair statement of the Company’s financial position as of March 31, 2022, and the results of its operations for the three months ended March 31, 2022 and 2021, its statements of stockholders’ equity for the three months ended March 31, 2022 and 2021, and its cash flows for the three months ended March 31, 2022 and 2021. The results of operations for the three months ended March 31, 2022 and 2021 are not necessarily indicative of the results that may be expected for the full year or any other subsequent interim period.
Principles of Consolidation	Principles of Consolidation ​ The accompanying condensed consolidated financial statements include the accounts of Ironwood and its wholly-owned subsidiaries as of March 31, 2022, Ironwood Pharmaceuticals Securities Corporation and Ironwood Pharmaceuticals GmbH. All intercompany transactions and balances are eliminated in consolidation.
Reclassifications	Reclassifications ​
Use of Estimates	Use of Estimates ​ The preparation of condensed 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 condensed 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 condensed 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.
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 three months ended March 31, 2022 that had a material effect on its condensed consolidated financial statements. ​ 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 ​ The Company adopted ASU 2020-06 on January 1, 2022 using the modified retrospective approach, which resulted in a cumulative-effect adjustment ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ Effect of the Adoption ​ January 1, 2022 Consolidated Balance Sheet As Reported of ASU 2020-06 As Adjusted Deferred tax assets ​ $ 333,294 ​ $ 16,855 ​ $ 350,149 Current portion of convertible senior notes ​ ​ 116,858 ​ ​ 3,581 ​ ​ 120,439 Long-term portion of convertible senior notes ​ ​ 337,333 ​ ​ 57,324 ​ ​ 394,657 Additional paid-in-capital ​ ​ 1,543,357 ​ ​ (110,217) ​ ​ 1,433,140 Retained earnings ​ ​ (937,608) ​ ​ 66,167 ​ ​ (871,441) ​ Interest expense recognized in future periods is expected to be reduced as a result of accounting for convertible debt instruments as a single liability measured at amortized cost, with an expected decrease of $22.1 million of non-cash interest expense during the year ended December 31, 2022 compared to the year ended December 31, 2021 related to convertible debt instruments outstanding on the adoption date. ​ The adoption of ASU 2020-06 does not impact the Company’s liquidity or cash flows. ​ 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 (“ASU 2021-04”). The guidance in ASU 2021-04 clarifies and reduces diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options that remain equity classified after modification or exchange. The standard is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. The Company adopted ASU 2021-04 as of January 1, 2022 . The adoption of ASU 2021-04 did not have a material impact on the Company’s financial position and results of operations. ​ 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 condensed consolidated financial statements upon future adoption.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
Schedule of ASU 2020-06 cumulative-effect adjustment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ Effect of the Adoption ​ January 1, 2022 Consolidated Balance Sheet As Reported of ASU 2020-06 As Adjusted Deferred tax assets ​ $ 333,294 ​ $ 16,855 ​ $ 350,149 Current portion of convertible senior notes ​ ​ 116,858 ​ ​ 3,581 ​ ​ 120,439 Long-term portion of convertible senior notes ​ ​ 337,333 ​ ​ 57,324 ​ ​ 394,657 Additional paid-in-capital ​ ​ 1,543,357 ​ ​ (110,217) ​ ​ 1,433,140 Retained earnings ​ ​ (937,608) ​ ​ 66,167 ​ ​ (871,441) ​

Net Income Per Share (Tables)

Net Income Per Share (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
Schedule of computation of basic and diluted net loss per common share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ ​ 2022 2021 ​ Numerator: ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 38,801 ​ $ 39,926 ​ Add back interest expense, net of tax benefit, on assumed conversion of 2024 Convertible Notes ​ ​ 444 ​ ​ — ​ Add back interest expense, net of tax benefit, on assumed conversion of 2026 Convertible Notes ​ ​ 666 ​ ​ — ​ Numerator used in computing net income per share — diluted ​ ​ 39,911 ​ ​ 39,926 ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — basic ​ ​ 157,821 ​ ​ 160,967 ​ Effect of dilutive securities: ​ ​ ​ ​ ​ ​ ​ Stock options ​ ​ 324 ​ ​ 268 ​ Time-based restricted stock units ​ ​ 1,132 ​ ​ 957 ​ Performance-based restricted stock units ​ ​ 222 ​ ​ 13 ​ Restricted stock ​ ​ 166 ​ ​ 136 ​ Shares subject to issuance under Employee Stock Purchase Plan ​ ​ 7 ​ ​ 6 ​ 2024 Convertible Notes assumed conversion ​ ​ 14,934 ​ ​ — ​ 2026 Convertible Notes assumed conversion ​ ​ 14,934 ​ ​ — ​ Dilutive potential common shares ​ ​ ​ ​ ​ ​ ​ Weighted average number of common shares outstanding used in computing net income per share — diluted ​ ​ 189,540 ​ ​ 162,347 ​ Net income per share — basic ​ $ 0.25 ​ $ 0.25 ​ Net income per share — diluted ​ $ 0.21 ​ $ 0.25 ​ ​
Schedule of potentially dilutive securities that have been excluded from computation of diluted weighted average shares outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2022 2021 ​ Stock options ​ 6,890 ​ 10,566 ​ Restricted stock awards — ​ 25 ​ Time-based restricted stock units ​ 114 ​ 407 ​ Performance-based restricted stock units ​ 858 ​ 20 ​ Note Hedge Warrants ​ 8,318 ​ 8,318 ​ 2022 Convertible Notes ​ — ​ 8,318 ​ 2024 Convertible Notes ​ — ​ 14,934 ​ 2026 Convertible Notes ​ — ​ 14,934 ​ Total 16,180 57,522 ​ ​

Collaboration, License, and O_2

Collaboration, License, and Other Agreements (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
Schedule of revenue attributable to transactions from collaboration and license arrangements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ Collaborative Arrangements Revenue ​ 2022 2021 ​ Linaclotide Collaboration and License Agreements: ​ ​ ​ ​ ​ ​ ​ AbbVie (North America) ​ $ 94,901 ​ $ 86,499 ​ AbbVie (Europe and other) ​ ​ 610 ​ ​ 600 ​ AstraZeneca (China, including Hong Kong and Macau) ​ ​ 192 ​ 210 ​ Astellas (Japan) ​ ​ 523 ​ 496 ​ Co-Promotion and Other Agreements: ​ ​ ​ ​ ​ ​ ​ Alnylam (GIVLAARI) ​ ​ 823 ​ ​ 456 ​ Other ​ ​ 480 ​ ​ 404 ​ Total collaborative arrangements revenue ​ $ 97,529 ​ $ 88,665 ​ Sale of API Linaclotide Agreements: ​ ​ ​ ​ ​ ​ ​ AstraZeneca (China, including Hong Kong and Macau) ​ $ — ​ $ 21 ​ Other ​ ​ — ​ ​ 159 ​ Total sale of API ​ $ — ​ $ 180 ​ ​
AbbVie
Table Text Blocks
Schedule of revenue attributable to transactions from collaboration and license arrangements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2022 2021 Collaborative arrangements revenue related to sales of LINZESS in the U.S. ​ $ 94,319 ​ $ 85,949 ​ Royalty revenue ​ 582 ​ 550 ​ Total collaborative arrangements revenue ​ $ 94,901 ​ $ 86,499 ​ ​ ​

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
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 ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ March 31, 2022 ​ ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 278,970 ​ ​ $ 278,970 ​ $ — ​ $ — Repurchase agreements ​ ​ 277,001 ​ ​ ​ 277,001 ​ ​ — ​ ​ — Restricted cash: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ ​ 1,735 ​ ​ ​ 1,735 ​ ​ — ​ ​ — Convertible note hedges ​ ​ 1,428 ​ ​ ​ — ​ ​ — ​ ​ 1,428 Total assets measured at fair value ​ $ 559,134 ​ ​ $ 557,706 ​ $ — ​ $ 1,428 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Note hedge warrants ​ $ 899 ​ ​ $ — ​ $ — ​ $ 899 Total liabilities measured at fair value ​ $ 899 ​ ​ $ — ​ $ — ​ $ 899 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting Date Using ​ ​ ​ Quoted Prices in Significant Other Significant ​ ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ December 31, 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 ​
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 March 31, 2022 and December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ December 31, 2021 ​ ​ ​ Convertible Note Hedge ​ Convertible Note Hedge ​ ​ Note Hedges ​ Warrants Note Hedges ​ Warrants Risk-free interest rate (1) ​ ​ 0.4 % ​ 1.4 % ​ 0.2 % ​ 0.4 % Expected term ​ 0.2 ​ 0.8 ​ ​ 0.5 ​ 1.0 ​ Stock price (2) ​ $ 12.58 ​ $ 12.58 ​ $ 11.66 ​ $ 11.66 ​ Strike price (3) ​ $ 14.51 ​ $ 18.82 ​ $ 14.51 ​ $ 18.82 ​ Common stock volatility (4) ​ ​ 31.9 % ​ 28.9 % ​ 27.0 % ​ 32.2 % 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 quarters ended March 31, 2022 and December 31, 2021, 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 assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible ​ Note Hedge ​ Note Hedges Warrants Balance at December 31, 2021 ​ $ 1,115 ​ $ (1,316) Change in fair value, recorded as a component of gain on derivatives ​ ​ 313 ​ ​ 417 Balance at March 31, 2022 ​ $ 1,428 ​ $ (899) ​
Schedule of the change in Level 3 liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible ​ Note Hedge ​ Note Hedges Warrants Balance at December 31, 2021 ​ $ 1,115 ​ $ (1,316) Change in fair value, recorded as a component of gain on derivatives ​ ​ 313 ​ ​ 417 Balance at March 31, 2022 ​ $ 1,428 ​ $ (899) ​ ​

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands):

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
Schedule of components of lease cost and supplemental cash flow information	Lease cost is recognized on a straight-line basis over the lease term. The components of lease cost for the three months ended March 31, 2022 and 2021 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ ​ 2022 ​ 2021 ​ Operating lease cost ​ $ 628 ​ $ 631 ​ Short-term lease cost ​ ​ 260 ​ ​ 214 ​ Total lease cost ​ $ 888 ​ $ 845 ​ ​ Supplemental information related to leases for the periods reported is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ 2022 ​ 2021 Cash paid for amounts included in the measurement of lease liabilities (in thousands) ​ $ 789 ​ ​ $ 773 ​ Weighted-average remaining lease term of operating leases (in years) ​ ​ 8.1 ​ ​ ​ 9.0 ​ Weighted-average discount rate of operating leases ​ ​ 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 March 31, 2022 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 (1) ​ $ 2,340 2023 ​ ​ 3,065 2024 ​ ​ 3,126 2025 ​ ​ 3,189 2026 ​ 3,252 2027 and thereafter ​ 11,603 Total future minimum lease payments ​ ​ 26,575 Less: present value adjustment ​ ​ (5,447) Operating lease liabilities ​ ​ 21,128 Less: current portion of operating lease liabilities ​ ​ (3,097) Operating lease liabilities, net of current portion ​ $ 18,031 (1) For the nine months ending December 31, 2022.

Notes Payable (Tables)

Notes Payable (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
Schedule of outstanding Convertible Note	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ 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) Less: unamortized debt issuance costs ​ ​ (5,065) ​ ​ (4,867) Net carrying amount ​ ​ 515,634 ​ ​ 454,191 Equity component: ​ ​ ​ ​ ​ ​ 2022 Convertible Notes ​ ​ — ​ ​ 19,807 2024 Convertible Notes ​ ​ — ​ ​ 41,152 2026 Convertible Notes ​ ​ — ​ ​ 51,350 Total equity component ​ $ — ​ $ 112,309
Schedule of interest expense related to Convertible Notes	​ The following table sets forth total interest expense recognized related to convertible senior notes during the three months ended March 31, 2022 and 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ 2022 2021 Contractual interest expense ​ $ 1,804 ​ $ 1,804 Amortization of debt issuance costs ​ ​ 537 ​ ​ 398 Amortization of debt discount ​ ​ — ​ ​ 5,424 Total interest expense ​ $ 2,341 ​ $ 7,626
Schedule of future minimum payments details of debt	Future minimum payments under the convertible senior notes as of March 31, 2022, are as follows (in thousands): ​ ​ ​ ​ 2022 (1) ​ $ 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 ​ ​ — Less: unamortized debt issuance costs ​ ​ (5,065) Convertible senior notes balance ​ $ 515,634 (1) For the nine months ending December 31, 2022.

Employee Stock Benefit Plans (T

Employee Stock Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Blocks
Share-based compensation expense reflected in the condensed consolidated statements of operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31, ​ ​ 2022 2021 Share-based compensation expense: ​ ​ ​ ​ ​ ​ ​ Research and development ​ $ 1,158 ​ $ 1,243 ​ Selling, general and administrative ​ ​ 4,931 ​ 4,043 ​ Restructuring expenses ​ ​ — ​ ​ 110 ​ Total share-based compensation expense included in operating expenses ​ ​ 6,089 ​ ​ 5,396 ​ Income tax expense (benefit) ​ ​ (720) ​ ​ — ​ Total share-based compensation expense, net of tax ​ $ 5,369 ​ $ 5,396 ​ ​

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - New Accounting Pronouncements (Details)	3 Months Ended
	Mar. 31, 2022
Accounting Standards Update 2020-06
New Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2022
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected	us-gaap:AccountingStandardsUpdate202006CumulativeEffectPeriodOfAdoptionMember
Accounting Standards Update 2021-04
New Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2022

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - ASU 2020-06 - Tabular Disclosure (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements
Deferred tax assets	$ 335,440	$ 333,294
Current portion of convertible senior notes	120,581	116,858
Long-term portion of convertible senior notes	395,053	337,333
Additional paid-in capital	1,350,268	1,543,357
Retained earnings	$ (832,640)	(937,608)
Cumulative Effect, Period of Adoption, Adjusted Balance
New Accounting Pronouncements
Deferred tax assets		350,149
Current portion of convertible senior notes		120,439
Long-term portion of convertible senior notes		394,657
Additional paid-in capital		1,433,140
Retained earnings		(871,441)
Accounting Standards Update 2020-06 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements
Deferred tax assets		16,855
Current portion of convertible senior notes		3,581
Long-term portion of convertible senior notes		57,324
Additional paid-in capital		(110,217)
Retained earnings		$ 66,167

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - ASU 2020-06 - Additional Information (Details) $ in Millions	Mar. 31, 2022USD ($)
Accounting Standards Update 2020-06
New Accounting Pronouncements
Interest expense, non-cash, expected increase (decrease) in current fiscal year	$ (22.1)

Net Income Per Share - Computat

Net Income Per Share - Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income	$ 38,801	$ 39,926
Net income (loss) available to common stockholders, basic	38,801	39,926
Net income (loss) available to common stockholders, diluted	$ 39,911	$ 39,926
Denominator:
Weighted average number of common shares outstanding used in computing net income per share - basic (in shares)	157,821	160,967
Effect of dilutive securities:
Weighted average number of common shares outstanding used in computing net income per share - diluted (in shares)	189,540	162,347
Net income per share - basic (in dollars per share)	$ 0.25	$ 0.25
Net income per share - diluted (in dollars per share)	$ 0.21	$ 0.25
Employee stock options
Effect of dilutive securities:
Effect of dilutive securities, share-based compensation	324	268
Time-based Restricted Stock Units
Effect of dilutive securities:
Effect of dilutive securities, share-based compensation	1,132	957
Performance-based Restricted Stock Units
Effect of dilutive securities:
Effect of dilutive securities, share-based compensation	222	13
Restricted Stock
Effect of dilutive securities:
Effect of dilutive securities, share-based compensation	166	136
Employee Stock
Effect of dilutive securities:
Effect of dilutive securities, share-based compensation	7	6
0.75% Convertible Senior Notes due 2024
Numerator:
Add back interest expense, net of tax benefit, on assumed conversion of convertible notes	$ 444
Effect of dilutive securities:
Effect of dilutive securities, convertible notes	14,934
1.50% Convertible Senior Notes due 2026
Numerator:
Add back interest expense, net of tax benefit, on assumed conversion of convertible notes	$ 666
Effect of dilutive securities:
Effect of dilutive securities, convertible notes	14,934

Net Income Per Share - Potentia

Net Income Per Share - Potentially Dilutive Securities (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	16,180	57,522
Employee stock options
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	6,890	10,566
Restricted Stock
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)		25
Time-based Restricted Stock Units
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	114	407
Performance-based Restricted Stock Units
Potentially dilutive securities
Total potentially dilutive securities excluded from the computation of diluted weighted average shares outstanding (in shares)	858	20
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
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
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
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

Collaboration, License, and O_3

Collaboration, License, and Other Agreements - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Revenue	$ 97,529	$ 88,845
Collaborative arrangements revenue
Revenues:
Revenue	97,529	88,665
Collaborative arrangement, other agreements
Revenues:
Revenue	480	404
Sale of active pharmaceutical ingredient
Revenues:
Revenue		180
AbbVie | Sale of active pharmaceutical ingredient
Revenues:
Revenue		159
AbbVie | North America | Collaborative arrangements revenue
Revenues:
Revenue	94,901	86,499
AbbVie | North America | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue	94,901	86,499
AbbVie | Europe and Other | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue	610	600
AstraZeneca | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue	192	210
AstraZeneca | Sale of active pharmaceutical ingredient
Revenues:
Revenue		21
Astellas Pharma Inc. | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue	523	496
Alnylam | Collaborative arrangement, co-promotion agreements
Revenues:
Revenue	$ 823	$ 456

Collaboration, License, and O_4

Collaboration, License, and Other Agreements - Accounts Receivable (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Accounts receivable, net
Accounts receivable, net	$ 119.7	$ 138
Accounts receivable, net of accounts payable	93.6	112.2
AbbVie
Accounts receivable, net
Accounts payable	$ 3.6	$ 5

Collaboration, License, and O_5

Collaboration, License, and Other Agreements - North America - General Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)paymentitem	Mar. 31, 2021USD ($)
Collaboration, License, Promotion and Other Commercial Agreements
Research and development expense	$ 10,822	$ 15,484
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
Sales-related milestone if certain conditions are met	$ 80,000
Remaining commercial-period performance obligations | item	3
Cost sharing amount, reduction to research and development	$ 2,400	2,900
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	$ 1,700	$ 1,800

Collaboration, License, and O_6

Collaboration, License, and Other Agreements - North America - Collaborative Arrangements Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Revenue	$ 97,529	$ 88,845
Collaborative arrangements revenue
Revenues:
Revenue	97,529	88,665
AbbVie | Royalty
Revenues:
Revenue	600	600
AbbVie | North America | Collaborative arrangements revenue
Revenues:
Revenue	94,901	86,499
AbbVie | North America | Collaborative arrangement, collaboration and license agreements
Revenues:
Revenue	94,901	86,499
AbbVie | North America | Collaborative arrangements, LINZESS
Revenues:
Revenue	94,319	85,949
AbbVie | North America | Royalty
Revenues:
Revenue	$ 582	$ 550

Collaboration, License, and O_7

Collaboration, License, and Other Agreements - North America - Commercial Efforts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 97,529	$ 88,845
Selling, general and administrative	28,861	27,652
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	97,529	88,665
Collaborative arrangements, LINZESS | AbbVie | U.S.
Collaboration, License, Promotion and Other Commercial Agreements
Selling, general and administrative	$ 8,700	$ 7,100

Collaboration, License, and O_8

Collaboration, License, and Other Agreements - North America - Royalty Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Revenue	$ 97,529	$ 88,845
Collaborative arrangements revenue
Revenues:
Revenue	97,529	88,665
Collaborative arrangements revenue | North America | AbbVie
Revenues:
Revenue	94,901	86,499
Collaborative arrangement, collaboration and license agreements | North America | AbbVie
Revenues:
Revenue	94,901	86,499
Royalty | AbbVie
Revenues:
Revenue	600	600
Royalty | North America | AbbVie
Revenues:
Revenue	582	550
Royalty | Canada and Mexico | AbbVie
Revenues:
Revenue	$ 600	$ 600

Collaboration, License, and O_9

Collaboration, License, and Other Agreements - European and Other Territories (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Oct. 31, 2015
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 97,529	$ 88,845
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	97,529	88,665
Collaborative arrangement, collaboration and license agreements | AbbVie | Europe and Other
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 610	600
License | AbbVie
Collaboration, License, Promotion and Other Commercial Agreements
Remaining milestone payment due upon the amendment to the license agreement			$ 42,500
Annual royalty	5 years
Royalty | AbbVie
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 600	$ 600

Collaboration, License, and _10

Collaboration, License, and Other Agreements - Japan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 97,529	$ 88,845
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	97,529	88,665
Collaborative arrangement, collaboration and license agreements | Astellas Pharma Inc.
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	523	496
Royalty | Astellas Pharma Inc., 2009 License Agreement, Amended 2019
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 500	500
Sale of active pharmaceutical ingredient
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		$ 180

Collaboration, License, and _11

Collaboration, License, and Other Agreements - China, Hong Kong and Macau (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2019USD ($)installment	Dec. 31, 2021USD ($)
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 97,529	$ 88,845
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	97,529	88,665
Sale of active pharmaceutical ingredient
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		180
AstraZeneca
Collaboration, License, Promotion and Other Commercial Agreements
Milestone payment to be received by company upon milestone achievement	90,000
Collaborative arrangement, significant financing component, transaction price	$ 2,600
Amount of non-contingent arrangement consideration			$ 35,000
Non-contingent consideration installments | installment			3
Percentage of tiered royalties	20.00%
Collaborative arrangement, non-contingent installment payments receivable	$ 25,000
Collaborative arrangement, non-contingent receivable, current	10,000
Collaborative arrangement, non-contingent receivable, non-current	14,100			$ 24,000
AstraZeneca | Collaborative arrangement, collaboration and license agreements
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	192	210
AstraZeneca | Royalty
Collaboration, License, Promotion and Other Commercial Agreements
Revenue	$ 200	100
AstraZeneca | Sale of active pharmaceutical ingredient
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		$ 21

Collaboration, License, and _12

Collaboration, License, and Other Agreements - Other Collaboration and License Agreements (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Nov. 30, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		$ 97,529	$ 88,845
Research and development expense		10,822	15,484
Accrued research and development costs		5,442		$ 15,896
Collaborative arrangements revenue
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		97,529	88,665
Alnylam | Collaborative arrangement, co-promotion agreements
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		823	456
Alnylam | Royalty
Collaboration, License, Promotion and Other Commercial Agreements
Revenue		800	$ 500
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
Collaborative arrangement, option to acquire license, exercise price, payable		35,000
Collaborative arrangement, milestones. potential commercial milestone payments, term of agreement, payable		440,000
Research and development expense				19,500
Accrued research and development costs		$ 3,800		$ 13,500

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - General Information (Details)	Mar. 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) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets:
Derivative Asset, Statement of Financial Position	Convertible note hedges	Convertible note hedges
Liabilities:
Derivative Liability, Statement of Financial Position	Note hedge warrants	Note hedge warrants
Recurring basis
Assets:
Convertible note hedges	$ 1,428	$ 1,115
Total assets measured at fair value	559,134	598,083
Liabilities:
Note hedge warrants	899	1,316
Total liabilities measured at fair value	899	1,316
Recurring basis | Money market funds
Assets:
Cash and cash equivalents	278,970	595,233
Restricted cash	1,735	1,735
Recurring basis | Repurchase agreements
Assets:
Cash and cash equivalents	277,001
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets measured at fair value	557,706	596,968
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets:
Cash and cash equivalents	278,970	595,233
Restricted cash	1,735	1,735
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Repurchase agreements
Assets:
Cash and cash equivalents	277,001
Recurring basis | Significant Unobservable Inputs (Level 3)
Assets:
Convertible note hedges	1,428	1,115
Total assets measured at fair value	1,428	1,115
Liabilities:
Note hedge warrants	899	1,316
Total liabilities measured at fair value	$ 899	$ 1,316

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Transfers Between Fair Value Measurement Levels (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair value transfers
Fair value transfer between measurement levels	$ 0	$ 0

Fair Value of Financial Instr_6

Fair Value of Financial Instruments - Assumptions - Convertible Note Hedges (Details)	Mar. 31, 2022$ / sharesY	Dec. 31, 2021Y$ / shares
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	0.004	0.002
Measurement Input, Expected Term
Fair Value of Financial Instruments
Derivative asset, measurement input | Y	0.2	0.5
Measurement Input, Share Price
Fair Value of Financial Instruments
Derivative asset, measurement input	12.58	11.66
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	0.319	0.270
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)	Mar. 31, 2022$ / sharesY	Dec. 31, 2021Y$ / shares
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	0.014	0.004
Measurement Input, Expected Term
Fair Value of Financial Instruments
Derivative liability, measurement input | Y	0.8	1
Measurement Input, Share Price
Fair Value of Financial Instruments
Derivative liability, measurement input	12.58	11.66
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	0.289	0.322
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) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)
Change in Level 3 Assets
Balance at beginning of period	$ 1,115
Change in fair value, recorded as a component of gain on derivatives	313
Balance at end of period	$ 1,428
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income	Gain on derivatives

Fair Value of Financial Instr_9

Fair Value of Financial Instruments - Change in Level 3 - Note Hedge Warrants (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)
Change in Level 3 Liabilities
Balance at beginning of period	$ (1,316)
Change in fair value, recorded as a component of gain on derivatives	417
Balance at end of period	$ (899)
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income	Gain on derivatives

Fair Value of Financial Inst_10

Fair Value of Financial Instruments - Notes Payable (Details) - Convertible Senior Notes - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	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
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	227,800	221,900
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	$ 236,500	$ 227,200

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

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Tabular Disclosure (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued Expenses
Accrued compensation and benefits	$ 10,086	$ 17,115
Accrued interest	2,105	301
Stock repurchase	1,002	3,009
Other	3,659	3,141
Total accrued expenses and other current liabilities	$ 16,852	$ 23,566

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued Expenses
Other accrued expenses	$ 3,659	$ 3,141
Other accrued liabilities, uninvoiced vendor liabilities	3,200	2,700
Income taxes payable	$ 300	$ 200

Leases - Collateral (Details)

Leases - Collateral (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Restricted Cash [Abstract]
Restricted cash	$ 1,735		$ 2,220
Money market funds
Restricted Cash [Abstract]
Restricted cash	$ 1,700	$ 1,700

Leases - Lease Cost - Tabular D

Leases - Lease Cost - Tabular Disclosure (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Lease cost
Operating lease cost	$ 628	$ 631
Short-term lease cost	260	214
Total lease cost	$ 888	$ 845

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating leases
Cash paid for amounts included in the measurement of lease liabilities	$ 789	$ 773
Weighted-average remaining lease term of operating leases (in years)	8 years 1 month 6 days	9 years
Weighted-average discount rate of operating leases (as a percent)	5.80%	5.80%

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Details) $ in Thousands	Mar. 31, 2022USD ($)
Future minimum lease payments
2022	$ 2,340
2023	3,065
2024	3,126
2025	3,189
2026	3,252
2027 and thereafter	11,603
Total future minimum lease payments	$ 26,575

Leases - Operating Lease Obliga

Leases - Operating Lease Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Operating lease obligations
Total future minimum lease payments	$ 26,575
Less: present value adjustment	(5,447)
Operating lease liabilities	21,128
Less: current portion of operating lease liabilities	(3,097)	$ (3,127)
Operating lease liabilities, net of current portion	$ 18,031	$ 18,484

Leases - Summer Street Lease (D

Leases - Summer Street Lease (Details) ft² in Thousands, $ in Thousands	1 Months Ended	3 Months Ended
	Jun. 30, 2019ft²	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2021USD ($)
Operating leases
Weighted-average discount rate of operating leases (as a percent)		5.80%	5.80%
Operating lease right-of-use assets		$ 15,028		$ 15,350
Operating lease liability		21,128
Operating lease cost		$ 628	$ 631
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		$ 15,000		15,300
Operating lease liability		21,100		$ 21,500
Operating lease cost		$ 600	$ 600

Notes Payable - General Informa

Notes Payable - General Information (Details)	1 Months Ended			3 Months Ended	12 Months Ended
	Aug. 31, 2019USD ($)	Apr. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / sharesshares	Mar. 31, 2022USD ($)$ / sharesshares	Dec. 31, 2019USD ($)	Dec. 31, 2021USD ($)	Apr. 15, 2019$ / shares
Notes Payable
Payments for convertible note hedges	$ 25,200,000		$ 21,100,000
Proceeds from partial termination of convertible note hedges and note hedge warrants	3,200,000
Convertible Note Hedge
Notes Payable
Conversion price (in dollars per share) | $ / shares				$ 16.58			$ 14.51
Shares issuable upon conversion of debt (in shares) | shares				20,249,665
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%
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%
Percentage of aggregate principal amount payable, in case of event of default			25.00%
Maximum period of the sole remedy for event failures in the Indenture				180 days
Debt redeemed/repurchased	215,000,000
Debt redemption/repurchase price	227,300,000
Loss on extinguishment of debt					$ 23,400,000
Equity component of convertible senior notes	$ (27,000,000)
Initial debt issuance costs					$ 2,800,000

Notes Payable - Convertible Sen

Notes Payable - Convertible Senior Notes - Balances (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Aug. 31, 2019	Jun. 30, 2015
Liability component:
Less: unamortized debt discount		$ (61,641)
Less: unamortized debt issuance costs	$ (5,065)	(4,867)
Net carrying amount	515,634	454,191
Total equity component		112,309
2.25% Convertible Senior Notes due 2022
Liability component:
Total equity component		19,807
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes
Liability component:
Aggregate principal amount of notes issued	120,699	120,699		$ 335,700
Less: unamortized debt discount		(3,500)
0.75% Convertible Senior Notes due 2024
Liability component:
Total equity component		41,152
0.75% Convertible Senior Notes due 2024 | Convertible Senior Notes
Liability component:
Aggregate principal amount of notes issued	200,000	200,000	$ 200,000
Less: unamortized debt discount		(22,300)
1.50% Convertible Senior Notes due 2026
Liability component:
Total equity component		51,350
1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes
Liability component:
Aggregate principal amount of notes issued	$ 200,000	200,000	$ 200,000
Less: unamortized debt discount		$ (35,800)

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	Mar. 31, 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		2.70%

Notes Payable - Convertible S_3

Notes Payable - Convertible Senior Notes - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Interest Expense
Contractual interest expense	$ 1,804	$ 1,804
Amortization of debt issuance costs	537	398
Amortization of debt discount		5,424
Total interest expense	$ 2,341	$ 7,626

Notes Payable - Convertible S_4

Notes Payable - Convertible Senior Notes - Future Minimum Payments - Tabular Disclosure (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
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	(5,065)	(4,867)
Net carrying amount	$ 515,634	$ 454,191

Notes Payable - Convertible S_5

Notes Payable - Convertible Senior Notes - Future Minimum Payments - Additional Information (Details) $ in Millions	Mar. 31, 2022USD ($)
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)	1 Months Ended
	Aug. 31, 2019USD ($)D$ / shares	Apr. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / sharesshares	Mar. 31, 2022USD ($)	Dec. 31, 2021USD ($)
Notes Payable
Payments for convertible note hedges	$ 25,200,000		$ 21,100,000
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%
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%
Percentage of aggregate principal amount payable, in case of event of default			25.00%
Debt instrument term			7 years
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
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
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%
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%
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%
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) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Aug. 31, 2019	Jun. 30, 2015	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Notes Payable
Unamortized debt discount					$ 61,641
Non-cash interest expense			$ 2,341	$ 7,626
2.25% Convertible Senior Notes due 2022 | Convertible Senior Notes
Notes Payable
Debt issuance costs incurred		$ 11,700
Debt issuance costs allocated to equity components		4,000
Debt issuance costs allocated to liability components		$ 7,700
Debt instrument term		7 years
Effective interest rate on liability components			2.70%
Unamortized debt discount					3,500
Non-cash interest expense				1,800
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes
Notes Payable
Debt issuance costs incurred	$ 9,000
Debt issuance costs allocated to equity components	2,100
Debt issuance costs allocated to liability components	$ 6,900
0.75% Convertible Senior Notes due 2024 | Convertible Senior Notes
Notes Payable
Debt instrument term	5 years
Effective interest rate on liability components			1.20%
Unamortized debt discount					22,300
Non-cash interest expense				2,000
1.50% Convertible Senior Notes due 2026 | Convertible Senior Notes
Notes Payable
Debt instrument term	7 years
Effective interest rate on liability components			1.90%
Unamortized debt discount					$ 35,800
Non-cash interest expense				$ 1,700

Notes Payable - Convertible Not

Notes Payable - Convertible Note Hedge and Warrant Transactions (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 15, 2019	Jun. 30, 2015	Mar. 31, 2022
Notes Payable
Warrants strike price (in dollars per share)	$ 18.82
Net derivative issuance cost		$ 21.1
Convertible Note Hedge
Notes Payable
Shares issuable upon conversion of debt (in shares)			20,249,665
Conversion price (in dollars per share)	$ 14.51		$ 16.58
Long-term asset		91.9
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		$ 70.8
Note Hedge Warrants
Notes Payable
Warrants strike price (in dollars per share)			$ 21.50
Note Hedge Warrants | 2.25% Convertible Senior Notes due 2022
Notes Payable
Shares issuable upon conversion of debt (in shares)	23,135,435

Notes Payable - Capped Calls wi

Notes Payable - 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 $ / shares in Units, $ in Millions	1 Months Ended
	Aug. 31, 2019USD ($)$ / shares$ / itemshares
Capped Calls
Payment made to enter into Capped Calls	$ 25.2
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
Equity component of issuance costs for convertible senior notes	$ 0.2

Employee Stock Benefit Plans -

Employee Stock Benefit Plans - Share-based Compensation Expense - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Stock Benefit Plans
Share-based compensation expense	$ 6,089	$ 5,396
Research and development
Employee Stock Benefit Plans
Share-based compensation expense	1,158	1,243
Selling, general and administrative
Employee Stock Benefit Plans
Share-based compensation expense	$ 4,931	4,043
Restructuring expenses
Employee Stock Benefit Plans
Share-based compensation expense		$ 110

Employee Stock Benefit Plans _2

Employee Stock Benefit Plans - Share-based Compensation Expense - Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Stock Benefit Plans
Share-based compensation expense	$ 6,089	$ 5,396
Income tax effect	(720)
Total share-based compensation expense included in costs and expenses, net of tax	$ 5,369	$ 5,396

Stock Repurchase Program (Detai

Stock Repurchase Program (Details) - USD ($) $ in Thousands, shares in Millions	1 Months Ended	3 Months Ended
	May 31, 2021	Mar. 31, 2022
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)		8
Common stock repurchased and retired		$ 90,489
Stock repurchase program, remaining authorized repurchase amount		$ 32,400

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Taxes
Income tax (benefit) expense	$ 17,664	$ 432

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2022	Mar. 31, 2022
Subsequent Event
Common stock repurchased and retired (in shares)		8
Common stock repurchased and retired		$ 90,489
Subsequent Event
Subsequent Event
Common stock repurchased and retired (in shares)	1.3
Common stock repurchased and retired, weighted-average price (in dollars per share)	$ 12.14
Common stock repurchased and retired	$ 15,900