Components of Net Deferred Tax Assets and Related Valuation Allowance (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Net operating loss carryforwards	$ 8,694	$ 6,394
Deferred revenue	3,165	6,552
Accrued expenses	736	1,233
Reserves and allowances	2,742	3,101
Share-based compensation	2,487	925
Other	512
Total deferred tax assets	18,336	18,205
Deferred tax liabilities:
Acquired intangible assets	(1,761)	(2,426)
Depreciation and amortization	(8,225)	(6,745)
Other		(294)
Total deferred tax liabilities	(9,986)	(9,465)
Valuation allowance	(3,023)	(2,581)
Net deferred tax assets	$ 5,327	$ 6,159