Warrant Liabilities - Additional Information (Detail) - USD ($)			1 Months Ended	3 Months Ended
	Feb. 12, 2016	Mar. 05, 2015	Jul. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Apr. 30, 2015
Class of Warrant or Right [Line Items]
Aggregate VWAP (percent)				1.00%
Decrease in the fair value of warrants liabilities				$ (1,170,000)	$ 6,174,000
Series A Warrants to Purchase Shares of Common Stock [Member] | IPO [Member]
Class of Warrant or Right [Line Items]
Number of common stock purchased upon issuance of warrants				2,449,605
Exercise price of warrants exercised				$ 6.50
Warrants term				5 years
Series A Warrant Liability [Member]
Class of Warrant or Right [Line Items]
Warrants exercised				24,000
Warrants outstanding				2,425,605
Warrant liability				$ 558,000		$ 1,213,000
Decrease in the fair value of warrants liabilities				655,000
Gross proceeds upon exercise of warrants				$ 0	156,000
Series A Warrant Liability [Member] | Common stock warrant liability [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding				2,425,605		2,425,605
Series B Warrants to Purchase Shares of Common Stock [Member]
Class of Warrant or Right [Line Items]
Number of common stock purchased upon issuance of warrants				2,449,605
Exercise price of warrants exercised				$ 6.50
Series B Warrant Liability [Member]
Class of Warrant or Right [Line Items]
Exercise price of warrants exercised		$ 6.50
Warrants exercised		589,510
Decrease in the fair value of warrants liabilities				$ 865,000
De-recognition of warrant liability		$ 6,700,000
Gross proceeds upon exercise of warrants		$ 3,800,000
Series B Warrant Liability [Member] | Cash Less Exercise [Member]
Class of Warrant or Right [Line Items]
De-recognition of warrant liability				$ 593,000	$ 417,000
Series B Warrant Liability [Member] | Common stock warrant liability [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding				0		116,580
Series B Warrant Liability [Member] | Common stock warrant liability [Member] | Cash Less Exercise [Member]
Class of Warrant or Right [Line Items]
Warrants exercised	102,300			102,300
De-recognition of Warrant liability upon exercise, shares issued	485,202			485,202
De-recognition of Warrant liability upon exercise	$ 594,000			$ 593,000
Series B Warrant Liability [Member] | Decrease in carrying value [Member]
Class of Warrant or Right [Line Items]
Decrease in the fair value of warrants liabilities				$ 271,000
Series C Warrant Liability [Member]
Class of Warrant or Right [Line Items]
Number of common stock purchased upon issuance of warrants				590,415
Exercise price of warrants exercised		$ 6.25					$ 6.25
Warrant liability				$ 219,000		$ 462,000
Decrease in the fair value of warrants liabilities				$ 244,000
Warrants cashless exercised			905
Proceeds from issuance of common stock under tender offer			$ 5,882
Series C Warrant Liability [Member] | Common stock warrant liability [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding				590,415		590,415
Series C Warrant Liability [Member] | Common Stock [Member]
Class of Warrant or Right [Line Items]
Issuance of shares upon cashless exercise warrants			905