Income Taxes Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss and capital loss carryforwards	$ 24,971	$ 25,445
Reserves and accruals	12,547	22,954
Stock-based compensation	10,074	16,399
Deferred revenue	10,811	13,975
Net translation losses	1,928	1,634
Credit carryforwards	792	679
Total deferred tax assets, gross	61,123	81,086
Deferred tax liabilities:
Depreciation and amortization	7,522	12,034
Unremitted foreign earnings	3,305	0
Prepaid expenses	751	969
Total deferred tax liabilities, gross	11,578	13,003
Net deferred tax assets before valuation allowance	49,545	68,083
Valuation allowance	(278)	(256)
Net deferred tax assets	$ 49,267	$ 67,827