Schedule of Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Components Of Deferred Tax Assets And Liabilities [Abstract]
Deferred tax assets, Net operating loss carryforwards	$ 214	$ 501
Deferred tax assets, Tax credits	1,372	2,984
Deferred tax assets, Intangible assets	11	24
Deferred tax assets, Deferred revenue adjustment	3,305	3,454
Deferred tax assets, Accrued Compensation	7,866	7,331
Share-based compensation expense	11,440	9,905
Deferred tax assets, Deferred rent	1,281	2,409
Deferred tax assets, Other	2,002	2,915
Deferred tax assets before valuation allowance	27,491	29,523
Deferred tax assets, Valuation allowance	(832)	(1,984)
Deferred tax assets, net of valuation allowance	26,659	27,539
Deferred tax liabilities, Prepaid expenses and other	1,098	1,389
Deferred tax liabilities, Property and equipment	10,821	12,253
Deferred tax liabilities, Capitalized software development costs	3,330	5,925
Total deferred tax liabilities	15,249	19,567
Total net deferred tax asset	11,410	7,972
Non-current deferred tax assets, net	11,704	7,989
Non-current deferred tax liabilities	$ (294)	$ (17)