Stockholder's Equity - Additional Information (Detail) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Jun. 21, 2016	Jul. 31, 2006	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Equity [Abstract]
Common stock, par value (in dollars per share)				$ 0.001		$ 0.001		$ 0.001
Common stock, shares authorized (in shares)				125,000,000		125,000,000		125,000,000
Common stock, shares issued (in shares)				26,478,051		26,478,051		24,609,411
Schedule of Capitalization, Equity [Line Items]
Number of warrants issued to purchase common stock (in shares)				14,033		14,033		14,033
Warrant liability fair value adjustment				$ 2,924,000	$ 101,000	$ 4,447,000	$ 101,000
Warrant liability				$ 2,154,000		$ 2,154,000		$ 6,601,000
Warrants to purchase common stock associated with Loan Agreement
Schedule of Capitalization, Equity [Line Items]
Number of warrants issued to purchase common stock (in shares)	122,435			122,435		122,435
Exercise price of warrants (in dollars per share)	$ 3.6754			$ 3.6754		$ 3.6754
Warrant expiration period	5 years					5 years
June 2016 Public Offering
Schedule of Capitalization, Equity [Line Items]
Number of warrants issued to purchase common stock (in shares)		4,218,750
Exercise price of warrants (in dollars per share)		$ 3.00
Number of shares received per warrant (in shares)		0.45
Warrant expiration period		5 years
Series C-1 Convertible Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Number of warrants issued to purchase common stock (in shares)			196,923
Exercise price of warrants (in dollars per share)			$ 3.25
Fair value of warrants			$ 500,000
Derivative Liability				$ 0		$ 0		$ 0
Common Stock
Schedule of Capitalization, Equity [Line Items]
Number of warrants issued to purchase common stock (in shares)			14,033
Exercise price of warrants (in dollars per share)			$ 45.61