Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Non-cancellable operating lease agreements, expiration year			2017
Total rent, property taxes and routine maintenance expense under operating leases	$ 223	$ 217	$ 692	$ 652
Current deferred rent	137		137		$ 126
Long-term deferred rent	$ 146		$ 146		$ 241