Income Taxes - Summary of Significant Components of Company's Net Deferred Income Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net deferred tax assets:
Net operating loss carryforwards	$ 178,597	$ 169,070
Stock-based compensation	21,603	29,884
U.S. tax credit carryforwards	16,489	13,526
Envisia asset acquisition	4,593	5,007
Basis difference in intangibles	0	7,625
Convertible Notes	(14,912)	(19,028)
Other assets	14,347	10,697
Other liabilities	(7,938)	(5,416)
Valuation allowance	(212,779)	(211,365)	$ (170,300)	$ (143,300)
Total net deferred income taxes	$ 0	$ 0