Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets
Total assets at fair value	$ 50,443	$ 60,743
Level 1 [Member]
Assets
Total assets at fair value	50,443	60,743
Money Market Funds [Member]
Assets
Total assets at fair value	50,443	60,743
Money Market Funds [Member] | Level 1 [Member]
Assets
Total assets at fair value	$ 50,443	$ 60,743