Stockholders' Equity - Summary of Company's Restricted Stock Award Activity (Detail) (Restricted stock [Member])	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2012
Restricted stock [Member]
Class Of Stock [Line Items]
Beginning balance, Unvested, Number of Shares	1,162,044	573,495	985,742	1,111,295
Granted, Number of Shares	55,000	0	60,000	1,380,000
Vested, Number of Shares	(221,302)	(262,245)	(472,247)	(1,233,409)
Canceled / forfeited, Number of Shares	(10,000)	(52,500)	0	(95,842)
Ending balance, Unvested, Number of Shares	985,742	258,750	573,495	1,162,044