Gross Amounts and Dates of Expiration of Tax Credits and Carryovers (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Federal losses carryovers	$ 676,762
California loss carryovers	80,227
Other state loss carryovers	53,967
Research credits	29,411	$ 28,892
Federal foreign tax credits	610
Federal
Income Tax Disclosure [Line Items]
Research credits	19,001
California
Income Tax Disclosure [Line Items]
Research credits	13,178
Expires 2022-2024
Income Tax Disclosure [Line Items]
Federal losses carryovers	76,223
Other state loss carryovers	620
Expires 2022-2024 | Federal
Income Tax Disclosure [Line Items]
Research credits	6,180
Expires 2025-2031
Income Tax Disclosure [Line Items]
Federal losses carryovers	183,062
California loss carryovers	41,407
Other state loss carryovers	870
Federal foreign tax credits	610
Expires 2025-2031 | Federal
Income Tax Disclosure [Line Items]
Research credits	1,539
Expires 2032-2041
Income Tax Disclosure [Line Items]
Federal losses carryovers	185,571
California loss carryovers	38,820
Other state loss carryovers	52,477
Expires 2032-2041 | Federal
Income Tax Disclosure [Line Items]
Research credits	11,282
No Expiration
Income Tax Disclosure [Line Items]
Federal losses carryovers	231,906
No Expiration | California
Income Tax Disclosure [Line Items]
Research credits	$ 13,178