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, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax provision at statutory rate	$ (8,490)	$ (16,202)	$ (15,076)
Tax on repatriated foreign earnings and other nondeductible items	403	195	179
Section 162(m) limitations	1,438	0	0
Change in tax credits	(3,738)	(2,148)	(2,361)
Change in valuation allowance	17,842	19,935	(19,792)
Change in tax rate	(4,058)	0	37,690
Stock option exercise (windfall) shortfall	(1,763)	257	0
Foreign tax and other	(1,365)	(1,788)	(436)
Total provision for income taxes	$ 269	$ 249	$ 204