Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Reserves and accruals	$ 2,817	$ 2,662
Deferred revenue	10,379	8,724
Stock-based compensation	7,361	4,772
Net operating loss carryforwards	47,452	37,793
Loss on OCI	370	374
Other	67	32
Gross deferred tax assets	68,446	54,357
Valuation allowance	(68,227)	(53,468)
Total deferred tax assets	219	889
Deferred tax liabilities:
Stock-based compensation	(21)	(21)
Depreciation and amortization	(243)	(1,425)
Total deferred tax liabilities	(264)	(1,446)
Net deferred tax liability	$ (45)	$ (557)