Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Reserves and accruals	$ 16,413	$ 21,048
Net operating loss carryovers	27,023	24,946
Research and development credit carryovers	27,595	26,404
Deferred stock-based compensation	5,834	6,727
Other tax credits	2,738	2,738
Gross deferred tax assets	79,603	81,863
Valuation allowance	(64,545)	(75,199)	$ (38,644)	$ (34,347)
Gross deferred tax assets after valuation allowance	15,058	6,664
Deferred tax liabilities:
Depreciation and amortization	(1,189)	(2,137)
Intangibles	(899)	(2,228)
Convertible notes	(10,233)	0
Other	(510)	(589)
Gross deferred tax liabilities	(12,831)	(4,954)
Net deferred tax assets	$ 2,227	$ 1,710