Income Taxes - Income Tax Expense (Benefit) Differed from Amounts Computed by Applying Statutory Federal Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax provision at federal statutory rate	$ (23,063)	$ (8,490)	$ (16,202)
Tax on repatriated foreign earnings and other nondeductible items	348	403	195
Section 162(m) limitations	5,044	1,438	0
Change in tax credits	3,123	(3,738)	(2,148)
Change in valuation allowance	21,707	17,842	19,935
Changes in federal and state tax rates	586	(4,058)	0
Stock option exercise (windfall) shortfall	(7,683)	(1,763)	257
Adjustments to deferred stock compensation	3,060	0	0
State and Foreign tax, and other	(2,869)	(1,365)	(1,788)
Total provision for income taxes	$ 253	$ 269	$ 249