Summary of Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Net operating losses and credit carryforwards	$ 58,798	$ 62,307
Stock options	5,299	5,513
Deferred rent	1,692	196
Deferred revenue	13	44
Accrued expenses	792	1,310
Other	367	0
Total deferred tax assets	66,961	69,370
Valuation allowance	(1,229)	(49,146)
Net deferred tax assets	65,732	20,224
Deferred tax liabilities:
Property and equipment	(18,777)	(20,012)
Other	(627)	(212)
Total deferred tax liabilities	(19,404)	(20,224)
Net deferred tax assets	$ 46,328	$ 0