Income Taxes Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss and capital loss carryforwards	$ 31,247	$ 33,202
Credit carryforwards	1,932	1,446
Deferred revenue	24,432	15,685
Reserves and accruals	17,455	17,203
Translation gains	649	637
Stock-based compensation	16,523	11,964
Total deferred tax assets, gross	92,238	80,137
Deferred tax liabilities:
Prepaid expenses	601	709
Depreciation and amortization	8,555	6,878
Total deferred tax liabilities, gross	9,156	7,587
Net deferred tax assets before valuation allowance	83,082	72,550
Valuation allowance	(31,685)	(32,498)
Net deferred tax assets	$ 51,397	$ 40,052