Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	Jan. 01, 2018	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Product Information [Line Items]
Cumulative adjustment to accumulated deficit		$ (1,392,748)				$ (1,165,470)				$ (1,392,748)	$ (1,165,470)
Product sales allowances		24,571				27,939				24,571	27,939
Cost of product sales		$ 9,392	$ 7,170	$ 9,005	$ 10,622	$ 15,874	$ 17,195	$ 13,588	$ 14,962	$ 36,189	$ 61,619	$ 27,512
Accounting Standards Update 2014-09
Product Information [Line Items]
Gross product sales	$ 2,900
Cost of product sales	200
Accounting Standards Update 2014-09 | Product Sales Allowance
Product Information [Line Items]
Product sales allowances	1,100
Accounting Standards Update 2018-13
Product Information [Line Items]
Change in accounting principle, accounting standards update, adopted		true								true
Change in accounting principle, accounting standards update, immaterial effect		true								true
Accounting Standards Update 2016-13
Product Information [Line Items]
Change in accounting principle, accounting standards update, adopted		true								true
Change in accounting principle, accounting standards update, immaterial effect		true								true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020								Jan. 01, 2020
Cumulative Effect Period of Adoption Adjustment | Accounting Standards Update 2014-09
Product Information [Line Items]
Cumulative adjustment to accumulated deficit	$ (1,600)
Leasehold Improvements
Product Information [Line Items]
Estimated useful lives										5 years