Subsequent Events - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Apr. 17, 2015
Subsequent Event [Line Items]
Proceeds from issuance of common stock	$ (46)	$ 51,507
Subsequent Event [Member]
Subsequent Event [Line Items]
Issuance of common stock			1,251,784
Proceeds from issuance of common stock			$ 12,500