Amicus Therapeutics (FOLD) 10-Q 10 Aug 20 2020 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2020	Jul. 27, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	001-33497
Entity Registrant Name	Amicus Therapeutics, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	71-0869350
Entity Address, Address Line One	1 Cedar Brook Drive,
Entity Address, City or Town	Cranbury,
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	08512
City Area Code	(609)
Local Phone Number	662-2000
Title of 12(b) Security	Common Stock
Trading Symbol	FOLD
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		258,787,743
Entity Central Index Key	0001178879
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 164,573	$ 142,837
Investments in marketable securities	145,017	309,903
Accounts receivable	43,040	33,284
Inventories	12,979	14,041
Prepaid expenses and other current assets	18,275	20,008
Total current assets	383,884	520,073
Operating lease right-of-use assets, less accumulated amortization of $6,219 and $5,342 at June 30, 2020 and December 31, 2019, respectively	23,949	33,315
Property and equipment, less accumulated depreciation of $21,194 and $17,604 at June 30, 2020 and December 31, 2019, respectively	46,945	47,705
In-process research & development	23,000	23,000
Goodwill	197,797	197,797
Other non-current assets	25,876	28,317
Total Assets	701,451	850,207
Current liabilities:
Accounts payable	14,306	21,722
Accrued expenses and other current liabilities	85,478	99,901
Operating lease liabilities	8,516	7,189
Total current liabilities	108,300	128,812
Deferred reimbursements	8,906	8,906
Convertible notes	2,203	2,131
Senior secured term loan	147,834	147,374
Contingent consideration payable	20,027	22,681
Deferred income taxes	5,051	5,051
Operating lease liabilities	43,666	53,531
Other non-current liabilities	4,511	5,296
Total liabilities	340,498	373,782
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value, 500,000,000 shares authorized, 258,223,842 and 255,417,869 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively	2,614	2,598
Additional paid-in capital	2,250,849	2,227,225
Accumulated other comprehensive loss:
Foreign currency translation adjustment	4,865	2,785
Unrealized gain on available-for-sale securities	288	40
Warrants	12,387	12,387
Accumulated deficit	(1,910,050)	(1,768,610)
Total stockholders’ equity	360,953	476,425
Total Liabilities and Stockholders’ Equity	$ 701,451	$ 850,207

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accumulated depreciation and amortization on finance and operating lease right-of-use leases	$ 6,219	$ 5,342
Accumulated depreciation of property and equipment	$ 21,194	$ 17,604
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	258,223,842	255,417,869
Common stock, shares outstanding (in shares)	258,223,842	255,417,869

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue:
Net product sales	$ 62,353	$ 44,130	$ 122,878	$ 78,176
Cost of goods sold	6,676	5,367	13,228	9,422
Gross profit	55,677	38,763	109,650	68,754
Operating expenses:
Research and development	69,611	70,981	158,731	135,574
Selling, general, and administrative	34,657	42,578	74,872	86,881
Changes in fair value of contingent consideration payable	715	480	1,646	1,863
Depreciation and amortization	2,039	1,154	3,803	2,145
Total operating expenses	107,022	115,193	239,052	226,463
Loss from operations	(51,345)	(76,430)	(129,402)	(157,709)
Other income (expense):
Interest income	865	2,599	2,380	5,238
Interest expense	(3,635)	(4,625)	(7,364)	(11,079)
Loss on exchange of convertible notes	0	(4,501)	0	(40,624)
Other income (expense)	5,326	(877)	(2,990)	209
Loss before income tax	(48,789)	(83,834)	(137,376)	(203,965)
Income tax expense	(3,703)	(717)	(4,064)	(885)
Net loss attributable to common stockholders	$ (52,492)	$ (84,551)	$ (141,440)	$ (204,850)
Net loss attributable to common stockholders per common share - basic and diluted (in dollars per share)	$ (0.20)	$ (0.36)	$ (0.55)	$ (0.91)
Weighted-average common shares outstanding - basic and diluted (in shares)	257,973,329	238,089,824	257,548,623	225,848,013

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (52,492)	$ (84,551)	$ (141,440)	$ (204,850)
Other comprehensive gain (loss):
Foreign currency translation adjustment (loss) gain, net of tax impact of $(2,090), $30, $(554), and $30, respectively	(2,116)	1,881	2,080	77
Unrealized gain (loss) on available-for-sale securities, net of tax impact of $122, $220, $66, and $220, respectively	457	(22)	248	562
Other comprehensive income	(1,659)	1,859	2,328	639
Comprehensive loss	$ (54,151)	$ (82,692)	$ (139,112)	$ (204,211)

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment, tax expense (benefit)	$ (2,090)	$ 30	$ (554)	$ 30
Available-for-sale securities, tax expense (benefit)	$ 122	$ 220	$ 66	$ 220

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Warrants	Other Comprehensive Gain (Loss)	Accumulated Deficit
Balance (in shares) at Dec. 31, 2018		189,383,924
Balance at Dec. 31, 2018	$ 342,912	$ 1,942	$ 1,740,061	$ 13,063	$ 68	$ (1,412,222)
Increase (Decrease) in Stockholders' Equity
Stock issued from exercise of stock options, net (in shares)		1,139,628
Stock issued from exercise of stock options, net	6,760	$ 11	6,749
Stock issued from equity financing (in shares)		18,720,930
Stock issued from equity financing	188,994	$ 187	188,807
Restricted stock tax vesting (in shares)		400,310
Restricted stock tax vesting	(2,555)		(2,555)
Stock issued for contingent consideration (in shares)		771,804
Stock issued for contingent consideration	9,316	$ 8	9,308
Stock-based compensation	22,679		22,679
Warrants exercised (in shares)		101,787
Warrants exercised	812	$ 1	1,487	(676)
Equity component of the convertible notes (in shares)		43,995,139
Equity component of the convertible notes	215,476	$ 440	215,036
Termination of capped call confirmations	19,875		19,875
Unrealized holding gain (loss) on available-for-sale securities	562				562
Foreign currency translation adjustment	77				77
Net loss	(204,850)					(204,850)
Balance (in shares) at Jun. 30, 2019		254,513,522
Balance at Jun. 30, 2019	600,058	$ 2,589	2,201,447	12,387	707	(1,617,072)
Balance (in shares) at Mar. 31, 2019		230,180,714
Balance at Mar. 31, 2019	451,668	$ 2,347	1,970,607	12,387	(1,152)	(1,532,521)
Increase (Decrease) in Stockholders' Equity
Stock issued from exercise of stock options, net (in shares)		561,177
Stock issued from exercise of stock options, net	2,807	$ 5	2,802
Stock issued from equity financing (in shares)		18,720,930
Stock issued from equity financing	188,994	$ 187	188,807
Restricted stock tax vesting (in shares)		99,252
Restricted stock tax vesting	(615)		(615)
Stock-based compensation	9,935		9,935
Equity component of the convertible notes (in shares)		4,951,449
Equity component of the convertible notes	24,718	$ 50	24,668
Termination of capped call confirmations	5,243		5,243
Unrealized holding gain (loss) on available-for-sale securities	(22)				(22)
Foreign currency translation adjustment	1,881				1,881
Net loss	(84,551)					(84,551)
Balance (in shares) at Jun. 30, 2019		254,513,522
Balance at Jun. 30, 2019	$ 600,058	$ 2,589	2,201,447	12,387	707	(1,617,072)
Balance (in shares) at Dec. 31, 2019	255,417,869	255,417,869
Balance at Dec. 31, 2019	$ 476,425	$ 2,598	2,227,225	12,387	2,825	(1,768,610)
Increase (Decrease) in Stockholders' Equity
Stock issued from exercise of stock options, net (in shares)		1,609,235
Stock issued from exercise of stock options, net	10,733	$ 16	10,717
Restricted stock tax vesting (in shares)		1,196,738
Restricted stock tax vesting	(8,097)		(8,097)
Stock-based compensation	21,004		21,004
Unrealized holding gain (loss) on available-for-sale securities	248				248
Foreign currency translation adjustment	2,080				2,080
Net loss	$ (141,440)					(141,440)
Balance (in shares) at Jun. 30, 2020	258,223,842	258,223,842
Balance at Jun. 30, 2020	$ 360,953	$ 2,614	2,250,849	12,387	5,153	(1,910,050)
Balance (in shares) at Mar. 31, 2020		257,449,955
Balance at Mar. 31, 2020	402,594	$ 2,607	2,238,346	12,387	6,812	(1,857,558)
Increase (Decrease) in Stockholders' Equity
Stock issued from exercise of stock options, net (in shares)		650,288
Stock issued from exercise of stock options, net	4,656	$ 7	4,649
Restricted stock tax vesting (in shares)		123,599
Restricted stock tax vesting	(554)		(554)
Stock-based compensation	8,408		8,408
Unrealized holding gain (loss) on available-for-sale securities	457				457
Foreign currency translation adjustment	(2,116)				(2,116)
Net loss	$ (52,492)					(52,492)
Balance (in shares) at Jun. 30, 2020	258,223,842	258,223,842
Balance at Jun. 30, 2020	$ 360,953	$ 2,614	$ 2,250,849	$ 12,387	$ 5,153	$ (1,910,050)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net loss	$ (141,440)	$ (204,850)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of debt discount and deferred financing	532	2,104
Depreciation and amortization	3,803	2,145
Stock-based compensation	21,004	22,679
Loss on exchange of convertible debt	0	40,624
Non-cash changes in the fair value of contingent consideration payable	1,646	1,863
Foreign currency remeasurement loss	5,604	530
Changes in operating assets and liabilities:
Accounts receivable	(10,388)	(6,829)
Inventories	1,351	(1,908)
Prepaid expenses and other current assets	1,375	(3,523)
Accounts payable and accrued expenses	(23,916)	12,453
Other non-current assets and liabilities	(1,031)	(819)
Deferred reimbursements	0	(1,500)
Net cash used in operating activities	(141,460)	(137,031)
Investing activities
Sale and redemption of marketable securities	210,139	261,425
Purchases of marketable securities	(45,005)	(191,318)
Capital expenditures	(1,876)	(5,110)
Net cash provided by investing activities	163,258	64,997
Financing activities
Proceeds from issuance of common stock, net of issuance costs	0	188,994
Payment of finance leases	(38)	(98)
Purchase of vested restricted stock units	(8,097)	(2,555)
Proceeds from termination of capped call confirmations	0	19,875
Proceeds from exercise of stock options	10,734	6,760
Proceeds of exercise of warrants	0	812
Net cash provided by financing activities	2,599	213,788
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(3,476)	(941)
Net increase in cash, cash equivalents, and restricted cash at the end of the period	20,921	140,813
Cash, cash equivalents, and restricted cash at beginning of period	146,341	82,375
Cash, cash equivalents, and restricted cash at the end of period	167,262	223,188
Supplemental disclosures of cash flow information
Tenant improvements paid through lease incentives	455	0
Cash paid during the period for interest	10,709	9,302
Contingent consideration paid in shares	0	9,316
Capital expenditures unpaid at the end of period	$ 502	$ 837

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Amicus Therapeutics, Inc. (the "Company") is a global, patient-dedicated biotechnology company focused on discovering, developing, and delivering novel medicines for rare diseases. The Company has a portfolio of product opportunities led by the first, oral monotherapy for Fabry disease that has achieved widespread global approval, a differentiated biologic for Pompe disease in the clinic, and an industry leading rare disease gene therapy portfolio. The cornerstone of the Company's portfolio is Galafold ® (also referred to as "migalastat"), the first and only approved oral precision medicine for people living with Fabry disease who have amenable genetic variants. Migalastat is currently approved under the trade name Galafold ® in the United States ("U.S."), European Union ("E.U."), United Kingdom ("U.K."), and Japan, with multiple additional approvals granted and applications pending in several other geographies around the world. The lead biologics program of the Company's pipeline is Amicus Therapeutics GAA ("AT-GAA", also known as ATB200/AT2221, or cipaglucosidase alfa/miglustat), a novel, clinical-stage, potential best-in-class treatment paradigm for Pompe disease. In February 2019, the U.S. Food and Drug Administration ("FDA") granted Breakthrough Therapy designation ("BTD") to AT-GAA for the treatment of late onset Pompe disease. In the first quarter of 2020, the British Medicines and Healthcare Products Regulatory Agency issued a Promising Innovative Medicine designation for AT-GAA for the treatment of late-onset Pompe disease. The Company has established an industry leading gene therapy portfolio of potential therapies for people living with rare metabolic diseases, through a license with Nationwide Children's Hospital ("Nationwide Children's") and an expanded collaboration with the University of Pennsylvania ("Penn"). The Company's pipeline includes gene therapy programs in rare, neurologic lysosomal disorders ("LDs"), specifically: CLN6, CLN3, and CLN1 Batten disease, Pompe disease, Fabry disease, CDKL5 deficiency disorder ("CDD"), Mucopolysaccharidosis Type IIIB ("MPS IIIB"), as well as a next generation program in Mucopolysaccharidosis Type IIIA ("MPS IIIA"). This expanded collaboration with Penn also provides the Company with exclusive disease-specific access and option rights to develop potentially disruptive new gene therapy platform technologies and programs for most LDs and a broader portfolio of more prevalent rare diseases, including Rett Syndrome, Angelman Syndrome, Myotonic Dystrophy, and select other muscular dystrophies. In the first quarter of 2020, the FDA granted Fast Track designation to the CLN3 Batten disease gene therapy, AT-GTX-502, for the treatment of pediatric patients less than 18 years of age. The Company's operations have not yet been significantly impacted from the novel coronavirus (“COVID-19”) pandemic. The Company has maintained operations in all geographies, secured its global supply chain for its commercial and clinical products, and maintained its clinical trials, with minimal disruption. The Company believes its ability to continue to operate without any significant disruptions will depend on the continued health of its employees, the ongoing demand for Galafold ® and the continued operation of its global supply chain. The Company has continued to provide uninterrupted access to medicines for those in need of treatment, while prioritizing the health and safety of its global workforce. However, the Company's results of operations in future periods may be negatively impacted by unknown future impacts from the COVID-19 pandemic. The Company had an accumulated deficit of $1.9 billion as of June 30, 2020 and anticipates incurring losses through the fiscal year ending December 31, 2020 and beyond. The Company has historically funded its operations through stock offerings, debt issuances, Galafold ® revenues, collaborations, and other financing arrangements. In July 2020, the Company entered into a definitive agreement for a $400 million credit facility with Hayfin Capital Management (“2020 Senior Secured Term Loan”) with an interest rate equal to 3-month LIBOR, subject to a 1% floor, plus 6.5% per annum and requires interest-only payments until mid-2024 and matures in six years in 2026. This transaction resulted in net proceeds of $386.1 million, after deducting fees and estimated expenses. There were no warrants or equity conversion features associated with the 2020 Senior Secured Term Loan. Additionally, the Company used $156.3 million of the proceeds to voluntary settle the principal amount, accrued interest, and early settlement premiums of the Senior Secured Term Loan with BioPharma Credit PLC that was due in 2023. The remaining proceeds will be used for other general corporate and product development purposes. Based on current operating models, the Company believes that the current cash position, along with the net proceeds from the 2020 Senior Secured Term Loan and expected revenues, is sufficient to fund the Company's operations and ongoing research programs through to profitability. Potential future impact of the COVID-19 pandemic, future business development collaborations, pipeline expansion, and investment in manufacturing capabilities could impact the Company's future capital requirements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The Company has prepared the accompanying unaudited Consolidated Financial Statements in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10-01 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. In the opinion of management, the accompanying unaudited financial statements reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company's interim financial information. The accompanying unaudited Consolidated Financial Statements and related notes should be read in conjunction with the Company's financial statements and related notes as contained in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2019. For a complete description of the Company's accounting policies, please refer to the Annual Report on Form 10-K for the fiscal year ended December 31, 2019. Consolidation The Consolidated Financial Statements include the accounts of the Company and its subsidiaries. Intercompany accounts and transactions are eliminated in consolidation. Foreign Currency Transactions The functional currency for most of the Company's foreign subsidiaries is their local currency. For non-U.S. subsidiaries that transact in a functional currency other than the U.S. dollar, assets and liabilities are translated at current rates of exchange at the balance sheet date. Income and expense items are translated at the average foreign exchange rates for the period. Adjustments resulting from the translation of the financial statements of the Company's foreign operations into U.S. dollars are excluded from the determination of net income and are recorded in accumulated other comprehensive income, a separate component of stockholders' equity. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. Additionally, the Company assessed the impact COVID-19 pandemic has had on its operations and financial results as of June 30, 2020 and through the issuance of this report. The Company’s analysis was informed by the facts and circumstances as they were known to the Company. This assessment considered the impact COVID-19 may have on financial estimates and assumptions that affect the reported amounts of assets and liabilities and revenue and expenses. Cash, Cash Equivalents, Marketable Securities, and Restricted Cash The Company considers all highly liquid investments purchased with a maturity of three months or less at the date of acquisition to be cash equivalents. Marketable securities consist of fixed income investments with a maturity of greater than three months and other highly liquid investments that can be readily purchased or sold using established markets. These investments are classified as available-for-sale and are reported at fair value on the Company's Consolidated Balance Sheets. Unrealized holding gains and losses are reported within comprehensive income (loss) in the Statements of Comprehensive Loss. Fair value is based on available market information including quoted market prices, broker or dealer quotations, or other observable inputs. Restricted cash consists primarily of funds held to satisfy the requirements of certain agreements that are restricted in their use and is included in non-current assets on the Company's Consolidated Balance Sheets. Concentration of Credit Risk The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash, cash equivalents, and marketable securities. The Company maintains its cash and cash equivalents in bank accounts, which, at times, exceed federally insured limits. The Company invests its marketable securities in high-quality commercial financial instruments. The Company has not recognized any losses from credit risks on such accounts during any of the periods presented. The Company believes it is not exposed to significant credit risk on its cash, cash equivalents, or marketable securities. The Company is subject to credit risk from its accounts receivable related to its product sales of Galafold ® . The Company's accounts receivable at June 30, 2020 have arisen from product sales primarily in Europe and the U.S. The Company will periodically assess the financial strength of its customers and the geographic economic environments and conditions to establish allowances for anticipated losses, if any. For accounts receivable that have arisen from named patient sales, the payment terms are predetermined, and the Company evaluates the creditworthiness of each customer on a regular basis. As of June 30, 2020, the Company recorded an allowance for doubtful accounts of $0.1 million. Revenue Recognition The Company's net product sales consist of sales of Galafold ® for the treatment of Fabry disease. The Company has recorded revenue on sales where Galafold ® is available either on a commercial basis or through a reimbursed early access program ("EAP"). Orders for Galafold ® are generally received from distributors and pharmacies with the ultimate payor often a government authority. The Company recognizes revenue when its performance obligations to its customers have been satisfied, which occurs at a point in time when the pharmacies or distributors obtain control of Galafold ® . The transaction price is determined based on fixed consideration in the Company's customer contracts and is recorded net of estimates for variable consideration, which are third party discounts and rebates. The identified variable consideration is recorded as a reduction of revenue at the time revenues from the sale of Galafold ® are recognized. The Company recognizes revenue to the extent that it is probable that a significant revenue reversal will not occur in a future period. These estimates may differ from actual consideration received. The Company evaluates these estimates each reporting period to reflect known changes. The following table summarizes the Company's net product sales from Galafold ® disaggregated by geographic area: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 U.S. $ 20,807 $ 12,181 $ 38,579 $ 21,249 Ex-U.S. 41,546 31,949 84,299 56,927 Total net product sales $ 62,353 $ 44,130 $ 122,878 $ 78,176 Inventories and Cost of Goods Sold Inventories are stated at the lower of cost and net realizable value, determined by the first-in, first-out method. Inventories are reviewed periodically to identify slow-moving or obsolete inventory based on projected sales activity as well as product shelf-life. In evaluating the recoverability of inventories produced, the probability that revenue will be obtained from the future sale of the related inventory is considered and inventory value is written down for inventory quantities in excess of expected requirements. Expired inventory is disposed of and the related costs are recognized as cost of goods sold in the Consolidated Statements of Operations. Cost of goods sold includes the cost of inventory sold, manufacturing and supply chain costs, product shipping and handling costs, provisions for excess and obsolete inventory, as well as royalties payable. Leases The Company primarily enters into lease agreements for office space, equipment, and vehicles. The leases have varying terms, some of which could include options to renew, extend, and early terminate. The Company determines if an arrangement is a lease at contract inception. Operating leases are included in right-of-use ("ROU") assets and lease liabilities on the Consolidated Balance Sheets. ROU assets represent the Company's right to control the use of an explicitly or implicitly identified fixed asset for a period of time and lease liabilities represent the Company's obligation to make lease payments arising from the lease. Control of an underlying asset is conveyed to the Company if the Company obtains the rights to direct the use of and to obtain substantially all of the economic benefits from using the underlying asset. ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. Lease payments included in the measurement of the lease liability are comprised of fixed payments. Variable lease payments are excluded from the ROU asset and lease liability and are recognized in the period in which the obligation for those payments is incurred. Variable lease payments are presented in the Consolidated Statements of Operations in the same line item as expenses arising from fixed lease payments for operating leases. The Company has lease agreements that include lease and non-lease components, which the Company accounts for as a single lease component for all underlying asset categories. The lease term for all of the Company's leases include the non-cancellable period of the lease plus any additional periods covered by either a Company option to extend (or not to terminate) the lease that the Company is reasonably certain to exercise, or an option to extend (or not to terminate) the lease controlled by the lessor. Leases with an initial term of 12 months or less are not recorded on the Consolidated Balance Sheets. The Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company applies this policy to all underlying asset categories. Recent Accounting Developments - Guidance Adopted in 2020 ASU 2018-15 - In August 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): ("ASU 2018-15"), relating to a customer’s accounting for implementation, set-up, and other upfront costs incurred in a cloud computing arrangement that is hosted by a vendor. Under the new guidance, a customer will apply the same criteria for capitalizing implementation costs as it would for an arrangement that has a software license. The new guidance does not affect the accounting for the service element of a hosting arrangement that is a service contract. The new guidance also prescribes the balance sheet, income statement and cash flow classification of the capitalized software costs and related amortization expense and requires additional quantitative and qualitative disclosures. ASU 2018-15 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 for public companies. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. ASU 2018-13 - In August 2018, the FASB issued ASU 2018-03, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement ("ASU 2018-13"). The amendments modify the disclosure requirements in Topic 820. ASU 2018-13 is effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The amendments on (i) changes in unrealized gains and losses, (ii) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and (iii) the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. ASU 2017-04 - In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 simplifies the recognition and measurement of a goodwill impairment loss by eliminating Step 2 of the quantitative goodwill impairment test. The guidance requires a one-step impairment test in which an entity compares the fair value of a reporting unit with its carrying amount and recognizes an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value, if any. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019 and should be applied on a prospective basis. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. ASU 2016-13 - In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). ASU 2016-13 requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected and amends guidance on the impairment of financial instruments. ASU 2016-13 is effective for public companies who are SEC filers for fiscal years beginning after December 15, 2019, including interim periods within those years. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. Recent Accounting Developments - Guidance Not Yet Adopted ASU 2019-12 - In December 2019, the FASB issued ASU 2019-15, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes ("ASU 2019-12"). This new guidance removes specific exceptions to the general principles in Topic 740. It eliminates the need for an organization to analyze whether the following apply in a given period: (i) exception to the incremental approach for intraperiod tax allocation; (ii) exceptions to accounting for basis differences when there are ownership changes in foreign investments; and (iii) exception in interim period income tax accounting for year-to-date losses that exceed anticipated losses. ASU 2019-12 also improves financial statement preparers’ application of income tax-related guidance and simplifies the following: (i) franchise taxes that are partially based on income; (ii) transactions with a government that result in a step up in the tax basis of goodwill; (iii) separate financial statements of legal entities that are not subject to tax; and (iv) enacted changes in tax laws in interim periods. ASU 2019 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted for public business entities for periods for which financial statements have not yet been issued. The Company is currently assessing the impact that this standard will have on the Company's Consolidated Financial Statements upon adoption.

Cash, Cash Equivalents, Marketa

Cash, Cash Equivalents, Marketable Securities, and Restricted Cash	6 Months Ended
	Jun. 30, 2020
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash, Cash Equivalents, Marketable Securities, and Restricted Cash	Cash, Cash Equivalents, Marketable Securities, and Restricted Cash As of June 30, 2020, the Company held $164.6 million in cash and cash equivalents and $145.0 million of marketable securities which are reported at fair value on the Company's Consolidated Balance Sheets. Unrealized holding gains and losses are generally reported within accumulated other comprehensive loss in the Statements of Comprehensive Loss. If a decline in the fair value of a marketable security below the Company's cost basis is determined to be other-than-temporary or if an available-for-sale debt security’s fair value is determined to less than the amortized cost and the Company intends or is more than likely to sell the security before recovery and it is not considered a credit loss, such security is written down to its estimated fair value as a new cost basis and the amount of the write-down is included in earnings as an impairment charge. If the unrealized loss of an available-for-sale debt security is determined to be a result of credit loss the Company would recognize an allowance and the corresponding credit loss would be included in earnings. The Company regularly invests excess operating cash in deposits with major financial institutions, money market funds, notes issued by the U.S. government, as well as fixed income investments and U.S. bond funds, both of which can be readily purchased and sold using established markets. The Company believes that the market risk arising from its holdings of these financial instruments is mitigated as many of these securities are either government backed or of the highest credit rating. Investments that have original maturities greater than three months but less than one year are classified as current. Cash, cash equivalents and marketable securities are classified as current unless mentioned otherwise below and consisted of the following: As of June 30, 2020 (in thousands) Cost Gross Gross Fair Cash and cash equivalents $ 164,573 $ — $ — $ 164,573 Corporate debt securities 51,307 225 — 51,532 Commercial paper 59,803 103 (4) 59,902 Asset-backed securities 33,020 162 — 33,182 Money market 350 — — 350 Certificates of deposit 51 — — 51 $ 309,104 $ 490 $ (4) $ 309,590 Included in cash and cash equivalents $ 164,573 $ — $ — $ 164,573 Included in marketable securities 144,531 490 (4) 145,017 Total cash, cash equivalents, and marketable securities $ 309,104 $ 490 $ (4) $ 309,590 As of December 31, 2019 (in thousands) Cost Gross Gross Fair Cash and cash equivalents $ 142,837 $ — $ — $ 142,837 Corporate debt securities 145,875 121 (5) 145,991 Commercial paper 73,659 53 (2) 73,710 Asset-backed securities 77,731 79 — 77,810 U.S. government agency bonds 11,999 2 (10) 11,991 Money market 350 — — 350 Certificates of deposit 51 — — 51 $ 452,502 $ 255 $ (17) $ 452,740 Included in cash and cash equivalents $ 142,837 $ — $ — $ 142,837 Included in marketable securities (1) 309,665 255 (17) 309,903 Total cash, cash equivalents, and marketable securities $ 452,502 $ 255 $ (17) $ 452,740 ______________________________ (1) As of December 31, 2019 , $9.5 million of marketable securities have maturity dates greater than 12 months and are available to convert into cash, if needed. For the six months ended June 30, 2020 there were nominal realized gains. For the fiscal year ended December 31, 2019, there were no realized gains or losses. The cost of securities sold is based on the specific identification method. Unrealized loss positions in the marketable securities as of June 30, 2020 and December 31, 2019 reflect temporary impairments and are not a result of credit loss. Additionally, as these positions have been in a loss position for less than twelve months and the Company does not intend to sell these securities before recovery, the losses are recognized in other comprehensive gain (loss). The fair value of these marketable securities in unrealized loss positions was $17.7 million and $42.6 million as of June 30, 2020 and December 31, 2019, respectively. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows. (in thousands) June 30, 2020 June 30, 2019 Cash and cash equivalents $ 164,573 $ 220,578 Restricted cash 2,689 2,610 Cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows $ 167,262 $ 223,188

Inventories

Inventories	6 Months Ended
	Jun. 30, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of raw materials, work-in-process, and finished goods related to the manufacture of Galafold ® . The following table summarizes the components of inventories: (in thousands) June 30, 2020 December 31, 2019 Raw materials $ 1,872 $ 6,544 Work-in-process 4,571 3,660 Finished goods 6,536 3,837 Total inventories $ 12,979 $ 14,041

Debt

Debt	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Debt	Debt The Company's debt consists of the following: (in thousands) June 30, 2020 December 31, 2019 Senior Secured Term Loan due 2023: Principal $ 150,000 $ 150,000 Less: debt discount (1) (1,909) (2,315) Less: deferred financing (1) (257) (311) Net carrying value of the Senior Secured Term Loan $ 147,834 $ 147,374 Convertible Notes due 2023 (2) : Principal $ 2,825 $ 2,825 Less: debt discount (1) (591) (659) Less: deferred financing (1) (31) (35) Net carrying value of the Convertible Notes $ 2,203 $ 2,131 ______________________________ (1) Included in the Consolidated Balance Sheets within Convertible Notes and Senior Secured Term Loan and amortized to interest expense over the remaining life of the Convertible Notes and Senior Secured Term Loan using the effective interest rate method. (2) The Convertible Notes are currently convertible as the last reported sale price of the Company's common stock was equal to or more than 130% of the conversion price for at least 20 trading days of the 30 consecutive trading days ending on the last day of the quarter. During the six months ended June 30, 2019, the Company entered into separate, privately negotiated Exchange Agreements with a limited number of holders ("the Holders") of the unsecured Convertible Senior Notes due in 2023 ("the Convertible Notes"). Under the terms of the Exchange Agreements, the Holders agreed to exchange an aggregate principal amount of $247.2 million of Convertible Notes held by them in exchange for an aggregate of approximately 44.0 million shares of Company common stock, par value $0.01 per share. In addition, pursuant to the Exchange Agreements, the Company made aggregate cash payments of $1.3 million to the Holders to satisfy accrued and unpaid interest to the closing date of the transactions, along with cash in lieu of fractional shares. These transactions resulted in $215.0 million in additional paid-in-capital and common stock of $0.4 million on the Consolidated Balance Sheets as of June 30, 2019. Additionally, the Company recognized a net loss on the exchange of debt of $36.1 million and $4.5 million on the Consolidated Statements of Operations for the quarters ended March 31, 2019 and June 30, 2019, respectively. During the six months ended June 30, 2019, the Company terminated the Capped Call Confirmations related to the exchange of the Convertible Notes for proceeds of $19.9 million. The following table sets forth interest expense recognized related to the Company's debt for the three and six months ended June 30, 2020 and 2019, respectively: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 Contractual interest expense $ 3,410 $ 4,146 $ 6,995 $ 8,959 Amortization of debt discount $ 268 $ 423 $ 474 $ 1,982 Amortization of deferred financing $ 33 $ 39 $ 58 $ 122

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation The Company's Equity Incentive Plans consist of the Amended and Restated 2007 Equity Incentive Plan (the "Plan") and the 2007 Director Option Plan (the "2007 Director Plan"). The Plan provides for the granting of restricted stock units and options to purchase common stock in the Company to employees, directors, advisors, and consultants at a price to be determined by the Company's Board of Directors. The Plan is intended to encourage ownership of stock by employees and consultants of the Company and to provide additional incentives for them to promote the success of the Company's business. The 2007 Director Plan is intended to promote the recruiting and retention of highly qualified eligible directors and strengthen the commonality of interest between directors and stockholders by encouraging ownership of common stock of the Company. The Board of Directors, or its committee, is responsible for determining the individuals to be granted options, the number of options each individual will receive, the option price per share, and the exercise period of each option. Stock Option Grants The fair value of the stock options granted is estimated on the date of grant using a Black-Scholes option pricing model with the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Expected stock price volatility 74.9 % 74.2 % 75.2 % 74.2 % Risk free interest rate 0.4 % 2.0 % 1.6 % 2.4 % Expected life of options (years) (1) 5.67 5.68 5.67 5.68 Expected annual dividend per share $ — $ — $ — $ — ______________________________ (1) The average expected life is determined using actual historical data. A summary of the Company's stock options for the six months ended June 30, 2020 were as follows: Number of Weighted Average Exercise Weighted Average Remaining Aggregate (in thousands) (in millions) Options outstanding, December 31, 2019 16,724 $ 9.15 Granted 4,225 $ 9.72 Exercised (1,663) $ 6.45 Forfeited (497) $ 10.33 Expired (375) $ 13.31 Options outstanding, June 30, 2020 18,414 $ 9.40 6.9 $ 105.6 Vested and unvested expected to vest, June 30, 2020 17,144 $ 9.35 6.7 $ 99.4 Exercisable at June 30, 2020 10,660 $ 8.76 5.4 $ 68.2 As of June 30, 2020, the total unrecognized compensation cost related to non-vested stock options granted was $40.4 million and is expected to be recognized over a weighted average period of three years. Restricted Stock Units and Performance-Based Restricted Stock Units (collectively "RSUs") RSUs awarded under the Plan are generally subject to graded vesting and are contingent on an employee's continued service. RSUs are generally subject to forfeiture if employment terminates prior to the release of vesting restrictions. The Company expenses the cost of the RSUs, which is determined to be the fair market value of the shares of common stock underlying the RSUs at the date of grant, ratably over the period during which the vesting restrictions lapse. A summary of non-vested RSU activity under the Plan for the six months ended June 30, 2020 is as follows: Number of Shares Weighted Weighted Aggregate (in thousands) (in millions) Non-vested units as of December 31, 2019 5,792 $ 11.18 Granted 3,731 $ 10.29 Vested (1,704) $ 9.04 Forfeited (335) $ 10.82 Non-vested units as of June 30, 2020 7,484 $ 11.21 2.6 $ 112.9 All non-vested units are expected to vest over their normal term. As of June 30, 2020, there was $69.3 million of total unrecognized compensation cost related to unvested RSUs with service-based vesting conditions. These costs are expected to be recognized over a weighted average period of three years. Compensation Expense Related to Equity Awards The following table summarizes information related to compensation expense recognized in the Consolidated Statements of Operations related to the equity awards: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 Equity compensation expense recognized in: Research and development expense $ 3,362 $ 3,952 $ 8,615 $ 8,984 Selling, general, and administrative expense 5,046 5,983 12,389 13,695 Total equity compensation expense $ 8,408 $ 9,935 $ 21,004 $ 22,679

Assets and Liabilities Measured

Assets and Liabilities Measured at Fair Value	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value	Assets and Liabilities Measured at Fair Value The Company's financial assets and liabilities are measured at fair value and classified within the fair value hierarchy, which is defined as follows: Level 1 — Quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 — Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly. Level 3 — Inputs that are unobservable for the asset or liability. A summary of the fair value of the Company's recurring assets and liabilities aggregated by the level in the fair value hierarchy within which those measurements fall as of June 30, 2020 are identified in the following table: (in thousands) Level 2 Total Assets: Commercial paper $ 59,902 $ 59,902 Asset-backed securities 33,182 33,182 Corporate debt securities 51,532 51,532 Money market funds 3,635 3,635 $ 148,251 $ 148,251 (in thousands) Level 2 Level 3 Total Liabilities: Contingent consideration payable $ — $ 24,327 $ 24,327 Deferred compensation plan liability 3,312 — 3,312 $ 3,312 $ 24,327 $ 27,639 A summary of the fair value of the Company's recurring assets and liabilities aggregated by the level in the fair value hierarchy within which those measurements fall as of December 31, 2019 are identified in the following table: (in thousands) Level 2 Total Assets: Commercial paper $ 73,710 $ 73,710 Asset-backed securities 77,810 77,810 Corporate debt securities 145,991 145,991 U.S. government agency bonds 11,991 11,991 Money market funds 4,768 4,768 $ 314,270 $ 314,270 (in thousands) Level 2 Level 3 Total Liabilities: Contingent consideration payable $ — $ 22,681 $ 22,681 Deferred compensation plan liability 4,419 — 4,419 $ 4,419 $ 22,681 $ 27,100 The Company's Convertible Notes fall into the Level 2 category within the fair value level hierarchy. The fair value was determined using broker quotes in a non-active market for valuation. The fair value of the Convertible Notes at June 30, 2020 was $7.3 million. The Company's Senior Secured Term Loan fall into the Level 2 category within the fair value level hierarchy and the fair value was determined using quoted prices for similar liabilities in active markets, as well as inputs that are observable for the liability (other than quoted prices), such as interest rates that are observable at commonly quoted intervals. The carrying value of the Senior Secured Term Loan approximates the fair value. The Company did not have any Level 3 assets as of June 30, 2020 or December 31, 2019. Cash, Money Market Funds, and Marketable Securities The Company classifies its cash within the fair value hierarchy as Level 1 as these assets are valued using quoted prices in an active market for identical assets at the measurement date. The Company considers its investments in marketable securities as available-for-sale and classifies these assets and the money market funds within the fair value hierarchy as Level 2 primarily utilizing broker quotes in a non-active market for valuation of these securities. Contingent Consideration Payable The contingent consideration payable resulted from the acquisition of Callidus Biopharma, Inc. ("Callidus") in November 2013. The most recent valuation was determined using a probability weighted discounted cash flow valuation approach. Gains and losses are included in the Consolidated Statements of Operations. The current portion of the contingent consideration payable is included within the accrued expenses and other current liabilities on the Company's Consolidated Balance Sheets. The contingent consideration payable for Callidus has been classified as a Level 3 recurring liability as its valuation requires substantial judgment and estimation of factors that are not currently observable in the market. If different assumptions were used for the various inputs to the valuation approach, the estimated fair value could be significantly higher or lower than the fair value the Company determined. The following significant unobservable inputs were used in the valuation of the contingent consideration payable of Callidus for the ATB-200 Pompe program: Contingent Consideration Fair Value as of June 30, 2020 Valuation Technique Unobservable Input Range (in thousands) Discount rate 8.9% Clinical and regulatory milestones $ 23,673 Probability weighted discounted cash flow Probability of achievement of milestones 75% - 78% Projected year of payments 2021 - 2022 Contingent consideration liabilities are remeasured to fair value each reporting period using discount rates, probabilities of payment, and projected payment dates. Projected contingent payment amounts related to clinical and regulatory based milestones are discounted back to the current period using a discounted cash flow model. Increases in discount rates and the time to payment may result in lower fair value measurements. Increases or decreases in any of those inputs together, or in isolation, may result in a significantly lower or higher fair value measurement. There is no assurance that any of the conditions for the milestone payments will be met. The following table shows the change in the balance of contingent consideration payable for the three and six months ended June 30, 2020 and June 30, 2019, respectively: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 Balance, beginning of the period $ 23,612 $ 20,767 $ 22,681 $ 19,700 Changes in fair value during the period, included in the Consolidated Statements of Operations 715 480 1,646 1,863 Adjustment for contingent consideration paid in stock — — — (316) Balance, end of the period $ 24,327 $ 21,247 $ 24,327 $ 21,247

Basic and Diluted Net Loss per

Basic and Diluted Net Loss per Common Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Basic and Diluted Net Loss per Common Share	Basic and Diluted Net Loss per Common Share The following table provides a reconciliation of the numerator and denominator used in computing basic and diluted net loss attributable to common stockholders per common share: Three Months Ended June 30, Six Months Ended June 30, (in thousands, except per share amounts) 2020 2019 2020 2019 Numerator: Net loss attributable to common stockholders $ (52,492) $ (84,551) $ (141,440) $ (204,850) Denominator: Weighted average common shares outstanding — basic and diluted 257,973,329 238,089,824 257,548,623 225,848,013 Dilutive common stock equivalents would include the dilutive effect of common stock options, convertible debt units, RSUs, and warrants for common stock equivalents. Potentially dilutive common stock equivalents were excluded from the diluted earnings per share denominator for all periods because of their anti-dilutive effect. The table below presents potential shares of common stock that were excluded from the computation as they were anti-dilutive using the treasury stock method: As of June 30, (in thousands) 2020 2019 Options to purchase common stock 18,414 17,849 Convertible notes 462 462 Outstanding warrants, convertible to common stock 2,555 2,555 Unvested restricted stock units 7,484 5,885 Total number of potentially issuable shares 28,915 26,751

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company has prepared the accompanying unaudited Consolidated Financial Statements in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10-01 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. In the opinion of management, the accompanying unaudited financial statements reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company's interim financial information.
Consolidation	Consolidation The Consolidated Financial Statements include the accounts of the Company and its subsidiaries. Intercompany accounts and transactions are eliminated in consolidation.
Foreign Currency Transactions	Foreign Currency Transactions The functional currency for most of the Company's foreign subsidiaries is their local currency. For non-U.S. subsidiaries that transact in a functional currency other than the U.S. dollar, assets and liabilities are translated at current rates of exchange at the balance sheet date. Income and expense items are translated at the average foreign exchange rates for the period. Adjustments resulting from the translation of the financial statements of the Company's foreign operations into U.S. dollars are excluded from the determination of net income and are recorded in accumulated other comprehensive income, a separate component of stockholders' equity.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. Additionally, the Company assessed the impact COVID-19 pandemic has had on its operations and financial results as of June 30, 2020 and through the issuance of this report. The Company’s analysis was informed by the facts and circumstances as they were known to the Company. This assessment considered the impact COVID-19 may have on financial estimates and assumptions that affect the reported amounts of assets and liabilities and revenue and expenses.
Cash, Cash Equivalents, Marketable Securities and Restricted Cash	Cash, Cash Equivalents, Marketable Securities, and Restricted Cash The Company considers all highly liquid investments purchased with a maturity of three months or less at the date of acquisition to be cash equivalents. Marketable securities consist of fixed income investments with a maturity of greater than three months and other highly liquid investments that can be readily purchased or sold using established markets. These investments are classified as available-for-sale and are reported at fair value on the Company's Consolidated Balance Sheets. Unrealized holding gains and losses are reported within comprehensive income (loss) in the Statements of Comprehensive Loss. Fair value is based on available market information including quoted market prices, broker or dealer quotations, or other observable inputs.
Concentration of Credit Risk	Concentration of Credit Risk The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash, cash equivalents, and marketable securities. The Company maintains its cash and cash equivalents in bank accounts, which, at times, exceed federally insured limits. The Company invests its marketable securities in high-quality commercial financial instruments. The Company has not recognized any losses from credit risks on such accounts during any of the periods presented. The Company believes it is not exposed to significant credit risk on its cash, cash equivalents, or marketable securities. The Company is subject to credit risk from its accounts receivable related to its product sales of Galafold ®
Revenue Recognition	Revenue Recognition The Company's net product sales consist of sales of Galafold ® for the treatment of Fabry disease. The Company has recorded revenue on sales where Galafold ® is available either on a commercial basis or through a reimbursed early access program ("EAP"). Orders for Galafold ® are generally received from distributors and pharmacies with the ultimate payor often a government authority. The Company recognizes revenue when its performance obligations to its customers have been satisfied, which occurs at a point in time when the pharmacies or distributors obtain control of Galafold ® . The transaction price is determined based on fixed consideration in the Company's customer contracts and is recorded net of estimates for variable consideration, which are third party discounts and rebates. The identified variable consideration is recorded as a reduction of revenue at the time revenues from the sale of Galafold ® are recognized. The Company recognizes revenue to the extent that it is probable that a significant revenue reversal will not occur in a future period. These estimates may differ from actual consideration received. The Company evaluates these estimates each reporting period to reflect known changes.
Inventories and Cost of Goods Sold	Inventories and Cost of Goods Sold Inventories are stated at the lower of cost and net realizable value, determined by the first-in, first-out method. Inventories are reviewed periodically to identify slow-moving or obsolete inventory based on projected sales activity as well as product shelf-life. In evaluating the recoverability of inventories produced, the probability that revenue will be obtained from the future sale of the related inventory is considered and inventory value is written down for inventory quantities in excess of expected requirements. Expired inventory is disposed of and the related costs are recognized as cost of goods sold in the Consolidated Statements of Operations.
Leases	Leases The Company primarily enters into lease agreements for office space, equipment, and vehicles. The leases have varying terms, some of which could include options to renew, extend, and early terminate. The Company determines if an arrangement is a lease at contract inception. Operating leases are included in right-of-use ("ROU") assets and lease liabilities on the Consolidated Balance Sheets. ROU assets represent the Company's right to control the use of an explicitly or implicitly identified fixed asset for a period of time and lease liabilities represent the Company's obligation to make lease payments arising from the lease. Control of an underlying asset is conveyed to the Company if the Company obtains the rights to direct the use of and to obtain substantially all of the economic benefits from using the underlying asset. ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. Lease payments included in the measurement of the lease liability are comprised of fixed payments. Variable lease payments are excluded from the ROU asset and lease liability and are recognized in the period in which the obligation for those payments is incurred. Variable lease payments are presented in the Consolidated Statements of Operations in the same line item as expenses arising from fixed lease payments for operating leases. The Company has lease agreements that include lease and non-lease components, which the Company accounts for as a single lease component for all underlying asset categories. The lease term for all of the Company's leases include the non-cancellable period of the lease plus any additional periods covered by either a Company option to extend (or not to terminate) the lease that the Company is reasonably certain to exercise, or an option to extend (or not to terminate) the lease controlled by the lessor.
Recent Accounting Developments	Recent Accounting Developments - Guidance Adopted in 2020 ASU 2018-15 - In August 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): ("ASU 2018-15"), relating to a customer’s accounting for implementation, set-up, and other upfront costs incurred in a cloud computing arrangement that is hosted by a vendor. Under the new guidance, a customer will apply the same criteria for capitalizing implementation costs as it would for an arrangement that has a software license. The new guidance does not affect the accounting for the service element of a hosting arrangement that is a service contract. The new guidance also prescribes the balance sheet, income statement and cash flow classification of the capitalized software costs and related amortization expense and requires additional quantitative and qualitative disclosures. ASU 2018-15 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 for public companies. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. ASU 2018-13 - In August 2018, the FASB issued ASU 2018-03, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement ("ASU 2018-13"). The amendments modify the disclosure requirements in Topic 820. ASU 2018-13 is effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The amendments on (i) changes in unrealized gains and losses, (ii) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and (iii) the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. ASU 2017-04 - In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 simplifies the recognition and measurement of a goodwill impairment loss by eliminating Step 2 of the quantitative goodwill impairment test. The guidance requires a one-step impairment test in which an entity compares the fair value of a reporting unit with its carrying amount and recognizes an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value, if any. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019 and should be applied on a prospective basis. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. ASU 2016-13 - In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). ASU 2016-13 requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected and amends guidance on the impairment of financial instruments. ASU 2016-13 is effective for public companies who are SEC filers for fiscal years beginning after December 15, 2019, including interim periods within those years. The Company adopted this guidance on January 1, 2020. The adoption did not have a material impact on the Company's Consolidated Financial Statements or related disclosures. Recent Accounting Developments - Guidance Not Yet Adopted ASU 2019-12 - In December 2019, the FASB issued ASU 2019-15, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes ("ASU 2019-12"). This new guidance removes specific exceptions to the general principles in Topic 740. It eliminates the need for an organization to analyze whether the following apply in a given period: (i) exception to the incremental approach for intraperiod tax allocation; (ii) exceptions to accounting for basis differences when there are ownership changes in foreign investments; and (iii) exception in interim period income tax accounting for year-to-date losses that exceed anticipated losses. ASU 2019-12 also improves financial statement preparers’ application of income tax-related guidance and simplifies the following: (i) franchise taxes that are partially based on income; (ii) transactions with a government that result in a step up in the tax basis of goodwill; (iii) separate financial statements of legal entities that are not subject to tax; and (iv) enacted changes in tax laws in interim periods. ASU 2019 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted for public business entities for periods for which financial statements have not yet been issued. The Company is currently assessing the impact that this standard will have on the Company's Consolidated Financial Statements upon adoption.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Disaggregation of Revenue	The following table summarizes the Company's net product sales from Galafold ® disaggregated by geographic area: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 U.S. $ 20,807 $ 12,181 $ 38,579 $ 21,249 Ex-U.S. 41,546 31,949 84,299 56,927 Total net product sales $ 62,353 $ 44,130 $ 122,878 $ 78,176

Cash, Cash Equivalents, Marke_2

Cash, Cash Equivalents, Marketable Securities, and Restricted Cash (Tables)	6 Months Ended
	Jun. 30, 2020
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Schedule of cash, cash equivalents and marketable securities	Cash, cash equivalents and marketable securities are classified as current unless mentioned otherwise below and consisted of the following: As of June 30, 2020 (in thousands) Cost Gross Gross Fair Cash and cash equivalents $ 164,573 $ — $ — $ 164,573 Corporate debt securities 51,307 225 — 51,532 Commercial paper 59,803 103 (4) 59,902 Asset-backed securities 33,020 162 — 33,182 Money market 350 — — 350 Certificates of deposit 51 — — 51 $ 309,104 $ 490 $ (4) $ 309,590 Included in cash and cash equivalents $ 164,573 $ — $ — $ 164,573 Included in marketable securities 144,531 490 (4) 145,017 Total cash, cash equivalents, and marketable securities $ 309,104 $ 490 $ (4) $ 309,590 As of December 31, 2019 (in thousands) Cost Gross Gross Fair Cash and cash equivalents $ 142,837 $ — $ — $ 142,837 Corporate debt securities 145,875 121 (5) 145,991 Commercial paper 73,659 53 (2) 73,710 Asset-backed securities 77,731 79 — 77,810 U.S. government agency bonds 11,999 2 (10) 11,991 Money market 350 — — 350 Certificates of deposit 51 — — 51 $ 452,502 $ 255 $ (17) $ 452,740 Included in cash and cash equivalents $ 142,837 $ — $ — $ 142,837 Included in marketable securities (1) 309,665 255 (17) 309,903 Total cash, cash equivalents, and marketable securities $ 452,502 $ 255 $ (17) $ 452,740 ______________________________ (1) As of December 31, 2019
Schedule of cash, cash equivalents, and restricted cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows. (in thousands) June 30, 2020 June 30, 2019 Cash and cash equivalents $ 164,573 $ 220,578 Restricted cash 2,689 2,610 Cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows $ 167,262 $ 223,188

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2020
Inventory Disclosure [Abstract]
Schedule of inventories for the period	The following table summarizes the components of inventories: (in thousands) June 30, 2020 December 31, 2019 Raw materials $ 1,872 $ 6,544 Work-in-process 4,571 3,660 Finished goods 6,536 3,837 Total inventories $ 12,979 $ 14,041

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Schedule of liability components of long term debt	The Company's debt consists of the following: (in thousands) June 30, 2020 December 31, 2019 Senior Secured Term Loan due 2023: Principal $ 150,000 $ 150,000 Less: debt discount (1) (1,909) (2,315) Less: deferred financing (1) (257) (311) Net carrying value of the Senior Secured Term Loan $ 147,834 $ 147,374 Convertible Notes due 2023 (2) : Principal $ 2,825 $ 2,825 Less: debt discount (1) (591) (659) Less: deferred financing (1) (31) (35) Net carrying value of the Convertible Notes $ 2,203 $ 2,131 ______________________________ (1) Included in the Consolidated Balance Sheets within Convertible Notes and Senior Secured Term Loan and amortized to interest expense over the remaining life of the Convertible Notes and Senior Secured Term Loan using the effective interest rate method.
Components of total interest expense	The following table sets forth interest expense recognized related to the Company's debt for the three and six months ended June 30, 2020 and 2019, respectively: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 Contractual interest expense $ 3,410 $ 4,146 $ 6,995 $ 8,959 Amortization of debt discount $ 268 $ 423 $ 474 $ 1,982 Amortization of deferred financing $ 33 $ 39 $ 58 $ 122

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Fair Value of Options	The fair value of the stock options granted is estimated on the date of grant using a Black-Scholes option pricing model with the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Expected stock price volatility 74.9 % 74.2 % 75.2 % 74.2 % Risk free interest rate 0.4 % 2.0 % 1.6 % 2.4 % Expected life of options (years) (1) 5.67 5.68 5.67 5.68 Expected annual dividend per share $ — $ — $ — $ — ______________________________
Schedule of Stock Options Activity	A summary of the Company's stock options for the six months ended June 30, 2020 were as follows: Number of Weighted Average Exercise Weighted Average Remaining Aggregate (in thousands) (in millions) Options outstanding, December 31, 2019 16,724 $ 9.15 Granted 4,225 $ 9.72 Exercised (1,663) $ 6.45 Forfeited (497) $ 10.33 Expired (375) $ 13.31 Options outstanding, June 30, 2020 18,414 $ 9.40 6.9 $ 105.6 Vested and unvested expected to vest, June 30, 2020 17,144 $ 9.35 6.7 $ 99.4 Exercisable at June 30, 2020 10,660 $ 8.76 5.4 $ 68.2
Schedule of Non-Vested RSU Activity under the Plan	A summary of non-vested RSU activity under the Plan for the six months ended June 30, 2020 is as follows: Number of Shares Weighted Weighted Aggregate (in thousands) (in millions) Non-vested units as of December 31, 2019 5,792 $ 11.18 Granted 3,731 $ 10.29 Vested (1,704) $ 9.04 Forfeited (335) $ 10.82 Non-vested units as of June 30, 2020 7,484 $ 11.21 2.6 $ 112.9
Schedule of Equity Compensation Expenses	The following table summarizes information related to compensation expense recognized in the Consolidated Statements of Operations related to the equity awards: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 Equity compensation expense recognized in: Research and development expense $ 3,362 $ 3,952 $ 8,615 $ 8,984 Selling, general, and administrative expense 5,046 5,983 12,389 13,695 Total equity compensation expense $ 8,408 $ 9,935 $ 21,004 $ 22,679

Assets and Liabilities Measur_2

Assets and Liabilities Measured at Fair Value (Tables)	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Summary of assets and liabilities subject to fair value measurements	A summary of the fair value of the Company's recurring assets and liabilities aggregated by the level in the fair value hierarchy within which those measurements fall as of June 30, 2020 are identified in the following table: (in thousands) Level 2 Total Assets: Commercial paper $ 59,902 $ 59,902 Asset-backed securities 33,182 33,182 Corporate debt securities 51,532 51,532 Money market funds 3,635 3,635 $ 148,251 $ 148,251 (in thousands) Level 2 Level 3 Total Liabilities: Contingent consideration payable $ — $ 24,327 $ 24,327 Deferred compensation plan liability 3,312 — 3,312 $ 3,312 $ 24,327 $ 27,639 A summary of the fair value of the Company's recurring assets and liabilities aggregated by the level in the fair value hierarchy within which those measurements fall as of December 31, 2019 are identified in the following table: (in thousands) Level 2 Total Assets: Commercial paper $ 73,710 $ 73,710 Asset-backed securities 77,810 77,810 Corporate debt securities 145,991 145,991 U.S. government agency bonds 11,991 11,991 Money market funds 4,768 4,768 $ 314,270 $ 314,270 (in thousands) Level 2 Level 3 Total Liabilities: Contingent consideration payable $ — $ 22,681 $ 22,681 Deferred compensation plan liability 4,419 — 4,419 $ 4,419 $ 22,681 $ 27,100
Schedule of significant unobservable inputs used in the valuation of the contingent consideration payable	The following significant unobservable inputs were used in the valuation of the contingent consideration payable of Callidus for the ATB-200 Pompe program: Contingent Consideration Fair Value as of June 30, 2020 Valuation Technique Unobservable Input Range (in thousands) Discount rate 8.9% Clinical and regulatory milestones $ 23,673 Probability weighted discounted cash flow Probability of achievement of milestones 75% - 78% Projected year of payments 2021 - 2022
Schedule of changes in contingent consideration payable	The following table shows the change in the balance of contingent consideration payable for the three and six months ended June 30, 2020 and June 30, 2019, respectively: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2020 2019 2020 2019 Balance, beginning of the period $ 23,612 $ 20,767 $ 22,681 $ 19,700 Changes in fair value during the period, included in the Consolidated Statements of Operations 715 480 1,646 1,863 Adjustment for contingent consideration paid in stock — — — (316) Balance, end of the period $ 24,327 $ 21,247 $ 24,327 $ 21,247

Basic and Diluted Net Loss pe_2

Basic and Diluted Net Loss per Common Share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Schedule of reconciliation of the numerator and denominator used in computing basic and diluted net loss per common share	The following table provides a reconciliation of the numerator and denominator used in computing basic and diluted net loss attributable to common stockholders per common share: Three Months Ended June 30, Six Months Ended June 30, (in thousands, except per share amounts) 2020 2019 2020 2019 Numerator: Net loss attributable to common stockholders $ (52,492) $ (84,551) $ (141,440) $ (204,850) Denominator: Weighted average common shares outstanding — basic and diluted 257,973,329 238,089,824 257,548,623 225,848,013
Schedule of potential shares of common stock that were excluded from the computation as they were anti-dilutive using the treasury stock method	The table below presents potential shares of common stock that were excluded from the computation as they were anti-dilutive using the treasury stock method: As of June 30, (in thousands) 2020 2019 Options to purchase common stock 18,414 17,849 Convertible notes 462 462 Outstanding warrants, convertible to common stock 2,555 2,555 Unvested restricted stock units 7,484 5,885 Total number of potentially issuable shares 28,915 26,751

Description of Business (Detail

Description of Business (Details) - USD ($)	1 Months Ended
	Jul. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Accumulated deficit		$ (1,910,050,000)	$ (1,768,610,000)
2020 Senior Term Loan | Secured Debt | Subsequent Event | Senior Loans
Debt Instrument [Line Items]
Credit facility maximum borrowing amount	$ 400,000,000
Term	6 years
Proceeds from credit facility	$ 386,100,000
2020 Senior Term Loan | Secured Debt | Subsequent Event | London Interbank Offered Rate (LIBOR) | Minimum | Senior Loans
Debt Instrument [Line Items]
Variable rate (in percent)	1.00%
2020 Senior Term Loan | Secured Debt | Subsequent Event | London Interbank Offered Rate (LIBOR) | Maximum | Senior Loans
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)	6.50%
Senior Secured Term Loan due 2023 | Subsequent Event | Senior Loans
Debt Instrument [Line Items]
Repayments of credit facility	$ 156,300,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounting Policies [Abstract]
Allowance for doubtful accounts receivable	$ 100		$ 100
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net product sales	62,353	$ 44,130	122,878	$ 78,176
U.S.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net product sales	20,807	12,181	38,579	21,249
Ex-U.S.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net product sales	$ 41,546	$ 31,949	$ 84,299	$ 56,927

Cash, Cash Equivalents, Marke_3

Cash, Cash Equivalents, Marketable Securities, and Restricted Cash - Additional Information (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash and cash equivalents	$ 164,573,000	$ 142,837,000	$ 220,578,000
Available-for-sale debt securities	145,017,000	309,903,000
Realized gain (loss) on debt securities	0	0
Fair value of available-for-sale debt securities in unrealized loss positions	$ 17,700,000	$ 42,600,000

Cash, Cash Equivalents, Marke_4

Cash, Cash Equivalents, Marketable Securities, and Restricted Cash - Components (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Cash, Money Market Funds, and Marketable Securities
Cash and cash equivalents	$ 164,573	$ 142,837	$ 220,578
Fair Value, Cash balances	164,573	142,837
Cost, available-for-sale securities	144,531	309,665
Gross unrealized gain, available-for-sale securities	490	255
Gross unrealized loss, available-for-sale securities	(4)	(17)
Fair value, Available-for-sale debt securities	145,017	309,903
Cost, Cash balances and available-for-sale securities	309,104	452,502
Gross unrealized gain, Cash balances and available-for-sale securities	490	255
Gross unrealized loss, Cash balances and available-for-sale securities	(4)	(17)
Fair value, Cash balances and available-for-sale securities	309,590	452,740
Marketable securities with maturity date greater than 12 months		9,500
Corporate debt securities
Cash, Money Market Funds, and Marketable Securities
Corporate debt securities, Cost	51,307	145,875
Corporate debt securities, Gross Unrealized Gain	225	121
Corporate debt securities, Gross Unrealized Loss	0	(5)
Corporate debt securities, Fair Value	51,532	145,991
Commercial paper
Cash, Money Market Funds, and Marketable Securities
Cost, available-for-sale securities	59,803	73,659
Gross unrealized gain, available-for-sale securities	103	53
Gross unrealized loss, available-for-sale securities	(4)	(2)
Fair value, Available-for-sale debt securities	59,902	73,710
Asset-backed securities
Cash, Money Market Funds, and Marketable Securities
Corporate debt securities, Cost	33,020	77,731
Corporate debt securities, Gross Unrealized Gain	162	79
Corporate debt securities, Gross Unrealized Loss	0	0
Corporate debt securities, Fair Value	33,182	77,810
U.S. government agency bonds
Cash, Money Market Funds, and Marketable Securities
Corporate debt securities, Cost		11,999
Corporate debt securities, Gross Unrealized Gain		2
Corporate debt securities, Gross Unrealized Loss		(10)
Corporate debt securities, Fair Value		11,991
Money market
Cash, Money Market Funds, and Marketable Securities
Cost, available-for-sale securities	350	350
Gross unrealized gain, available-for-sale securities	0	0
Gross unrealized loss, available-for-sale securities	0	0
Fair value, Available-for-sale debt securities	350	350
Certificates of deposit
Cash, Money Market Funds, and Marketable Securities
Cost, available-for-sale securities	51	51
Gross unrealized gain, available-for-sale securities	0	0
Gross unrealized loss, available-for-sale securities	0	0
Fair value, Available-for-sale debt securities	$ 51	$ 51

Cash, Cash Equivalents, Marke_5

Cash, Cash Equivalents, Marketable Securities, and Restricted Cash - Cash, Cash Equivalents, And Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash and cash equivalents	$ 164,573	$ 142,837	$ 220,578
Restricted cash	2,689		2,610
Cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows	$ 167,262	$ 146,341	$ 223,188	$ 82,375

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 1,872	$ 6,544
Work-in-process	4,571	3,660
Finished goods	6,536	3,837
Total inventories	12,979	14,041
Reserve for inventory	$ 200	$ 200

Debt - Summary of Long Term Deb

Debt - Summary of Long Term Debt (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)day	Dec. 31, 2019USD ($)
Senior Loans | Senior Secured Term Loan due 2023
Debt Instrument [Line Items]
Long-term debt	$ 150,000	$ 150,000
Less: debt discount	(1,909)	(2,315)
Less: deferred financing	(257)	(311)
Net carrying value	147,834	147,374
Convertible Notes | Convertible Senior Notes 2016, Due 2023
Debt Instrument [Line Items]
Long-term debt	2,825	2,825
Less: debt discount	(591)	(659)
Less: deferred financing	(31)	(35)
Net carrying value	$ 2,203	$ 2,131
Threshold percentage	130.00%
Threshold consecutive trading days | day	30
Convertible Notes | Convertible Senior Notes 2016, Due 2023 | Minimum
Debt Instrument [Line Items]
Threshold trading days	20 days

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Debt Instrument [Line Items]
Exchange agreement, aggregate principal amount		$ 247,200			$ 247,200
Shares authorized for issuance (in shares)		44			44
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01		$ 0.01	$ 0.01	$ 0.01
Exchange agreement, accrued and unpaid interest					$ 1,300
Gain (loss) on extinguishment of debt, additional paid-in capital		$ 215,000			215,000
Gain (loss) on extinguishment of debt, fair value of common shares issued		400			400
Loss on exchange of convertible debt	$ 0	$ 4,501	$ 36,100	$ 0	40,624
Proceeds from termination of capped call confirmations				$ 0	$ 19,875

Debt - Interest Expense (Detail

Debt - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Disclosure [Abstract]
Contractual interest expense	$ 3,410	$ 4,146	$ 6,995	$ 8,959
Amortization of debt discount	268	423	474	1,982
Amortization of deferred financing	$ 33	$ 39	$ 58	$ 122

Share-Based Compensation - Weig

Share-Based Compensation - Weighted-average Assumptions (Details) - Options to purchase common stock - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected stock price volatility	74.90%	74.20%	75.20%	74.20%
Risk free interest rate	0.40%	2.00%	1.60%	2.40%
Expected life of options (years)	5 years 8 months 1 day	5 years 8 months 4 days	5 years 8 months 1 day	5 years 8 months 4 days
Expected annual dividend per share (in dollars per share)	$ 0	$ 0	$ 0	$ 0

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Activity (Details) - Options to purchase common stock - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended
	Jun. 30, 2020
Number of Shares
Options outstanding (in shares)	16,724
Options, Granted (in shares)	4,225
Options, Exercised (in shares)	(1,663)
Options, Forfeited (in shares)	(497)
Options, Expired (in shares)	(375)
Options outstanding (in shares)	18,414
Options, Vested and unvested expected to vest (in shares)	17,144
Options, Exercisable (in shares)	10,660
Weighted Average Exercise  Price
Options outstanding (in dollars per share)	$ 9.15
Options, Granted (in dollars per share)	9.72
Options, Exercised (in dollars per share)	6.45
Options, Forfeited (in dollars per share)	10.33
Options, Expired (in dollars per share)	13.31
Options outstanding (in dollars per share)	9.40
Options, Vested and unvested expected to vest (in dollars per share)	9.35
Options, Exercisable (in dollars per share)	$ 8.76
Additional Disclosures
Weighted average remaining contractual life, options outstanding	6 years 10 months 24 days
Weighted average remaining contractual life, options vested and unvested expected to vest	6 years 8 months 12 days
Weighted average remaining contractual life, options exercisable	5 years 4 months 24 days
Aggregate intrinsic value, options outstanding	$ 105.6
Aggregate intrinsic value, vested and unvested expected to vest	99.4
Aggregate intrinsic value, exercisable	$ 68.2

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)
Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation costs	$ 40.4
Unrecognized compensation costs, period for recognition (in years)	3 years
Unvested restricted stock units | Stock Option Plan Amended Restated 2007 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation costs	$ 69.3
Unrecognized compensation costs, period for recognition (in years)	3 years

Share-Based Compensation - RSUs

Share-Based Compensation - RSUs and PBRSUs Summary (Details) - Unvested restricted stock units - Stock Option Plan Amended Restated 2007 Equity Incentive Plan $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)$ / sharesshares
Number of Shares
Non-vested units (in shares) | shares	5,792
Granted (in shares) | shares	3,731
Vested (in shares) | shares	(1,704)
Forfeited (in shares) | shares	(335)
Non-vested units (in shares) | shares	7,484
Weighted Average Grant Date Fair Value
Non-vested units (in dollars per share) | $ / shares	$ 11.18
Granted (in dollars per share) | $ / shares	10.29
Vested (in dollars per share) | $ / shares	9.04
Forfeited (in dollars per share) | $ / shares	10.82
Non-vested units (in dollars per share) | $ / shares	$ 11.21
Additional Disclosures
Non-vested units, weighted average remaining years	2 years 7 months 6 days
Non-vested units, aggregate intrinsic value | $	$ 112.9

Share-Based Compensation - Expe

Share-Based Compensation - Expense Summary (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total equity compensation expense	$ 8,408	$ 9,935	$ 21,004	$ 22,679
Research and development expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total equity compensation expense	3,362	3,952	8,615	8,984
Selling, general, and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total equity compensation expense	$ 5,046	$ 5,983	$ 12,389	$ 13,695

Assets and Liabilities Measur_3

Assets and Liabilities Measured at Fair Value - Components by Hierarchy Level (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets:
Fair value of assets	$ 148,251	$ 314,270
Liabilities:
Contingent consideration payable	24,327	22,681
Deferred compensation plan liability	3,312	4,419
Fair value of liabilities	27,639	27,100
Commercial paper
Assets:
Fair value of assets	59,902	73,710
Asset-backed securities
Assets:
Fair value of assets	33,182	77,810
Corporate debt securities
Assets:
Fair value of assets	51,532	145,991
U.S. government agency bonds
Assets:
Fair value of assets		11,991
Money market funds
Assets:
Fair value of assets	3,635	4,768
Level 2
Assets:
Fair value of assets	148,251	314,270
Liabilities:
Contingent consideration payable	0	0
Deferred compensation plan liability	3,312	4,419
Fair value of liabilities	3,312	4,419
Fair value of the Convertible Notes	7,300
Level 2 | Commercial paper
Assets:
Fair value of assets	59,902	73,710
Level 2 | Asset-backed securities
Assets:
Fair value of assets	33,182	77,810
Level 2 | Corporate debt securities
Assets:
Fair value of assets	51,532	145,991
Level 2 | U.S. government agency bonds
Assets:
Fair value of assets		11,991
Level 2 | Money market funds
Assets:
Fair value of assets	3,635	4,768
Level 3
Liabilities:
Contingent consideration payable	24,327	22,681
Deferred compensation plan liability	0	0
Fair value of liabilities	$ 24,327	$ 22,681

Assets and Liabilities Measur_4

Assets and Liabilities Measured at Fair Value - Significant Unobservable Inputs (Details) $ in Thousands	Jun. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration payable	$ 24,327	$ 22,681
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration payable	24,327	$ 22,681
Callidus Biopharma Inc | Clinical and regulatory milestones | ATB200 Pompe Program
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration payable	$ 23,673
Callidus Biopharma Inc | Clinical and regulatory milestones | Probability of achievement of milestones | ATB200 Pompe Program | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	0.75
Callidus Biopharma Inc | Clinical and regulatory milestones | Probability of achievement of milestones | ATB200 Pompe Program | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	0.78
Callidus Biopharma Inc | Clinical and regulatory milestones | Level 3 | Discount rate | ATB200 Pompe Program | Probability weighted discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, measurement input	0.089

Assets and Liabilities Measur_5

Assets and Liabilities Measured at Fair Value - Level 3 Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of the period	$ 23,612	$ 20,767	$ 22,681	$ 19,700
Changes in fair value during the period, included in the Consolidated Statements of Operations	715	480	1,646	1,863
Adjustment for contingent consideration paid in stock	0	0	0	(316)
Balance, end of the period	$ 24,327	$ 21,247	$ 24,327	$ 21,247

Basic and Diluted Net Loss pe_3

Basic and Diluted Net Loss per Common Share (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net loss attributable to common stockholders	$ (52,492)	$ (84,551)	$ (141,440)	$ (204,850)
Denominator:
Weighted-average common shares outstanding - basic and diluted (in shares)	257,973,329	238,089,824	257,548,623	225,848,013
Antidilutive securities excluded from computation of diluted earnings per share (in shares)			28,915,000	26,751,000
Options to purchase common stock
Denominator:
Antidilutive securities excluded from computation of diluted earnings per share (in shares)			18,414,000	17,849,000
Convertible notes
Denominator:
Antidilutive securities excluded from computation of diluted earnings per share (in shares)			462,000	462,000
Outstanding warrants, convertible to common stock
Denominator:
Antidilutive securities excluded from computation of diluted earnings per share (in shares)			2,555,000	2,555,000
Unvested restricted stock units
Denominator:
Antidilutive securities excluded from computation of diluted earnings per share (in shares)			7,484,000	5,885,000