Analysis of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 333,703	$ 304,033
Difference in depreciation and amortization	31,259	40,095
Research and development tax credits	159,917	103,806
Stock-based compensation	31,212	24,114
Lease liabilities	13,120	15,796
Deferred revenue		939
Capitalized inventory	35,959	18,255
Other	28,381	16,270
Total deferred tax assets	633,551	523,308
Deferred tax liabilities:
Right of use asset	(8,772)	(10,782)
Debt discount	(18,044)	(23,099)
Total deferred tax liabilities	(26,816)	(33,881)
Valuation allowance	(605,848)	(488,829)
Net deferred tax assets	$ 887	$ 598