Liquidity, Financial Condition and Management's Plans - Additional Information (Detail)						3 Months Ended		6 Months Ended		11 Months Ended
	Jun. 29, 2016 USD ($) closing $ / shares shares	Jan. 08, 2016 USD ($)	Oct. 15, 2015 USD ($)	Oct. 12, 2015 USD ($) closing	Jul. 24, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) shares	Dec. 31, 2015 USD ($)
Liquidity And Managements Plans [Line Items]
Net loss						$ (3,513,000)	$ 1,881,000	$ (6,702,000)	$ (9,770,000)
Accumulated deficit						(92,948,000)		(92,948,000)		$ (92,948,000)	$ (86,247,000)
Positive (deficit) in working capital						$ 1,900,000		1,900,000		$ 1,900,000
Net cash used in operating activities								(8,024,000)	(4,060,000)
Proceeds from sale of Series A preferred convertible stock								5,071,000	0
Expenses related stock issuance								0	530,000
Series A Convertible Preferred Stock [Member]
Liquidity And Managements Plans [Line Items]
Expenses related stock issuance								$ 71,000	$ 0
2016 Sabby Purchase Agreement [Member] | Series A Convertible Preferred Stock [Member]
Liquidity And Managements Plans [Line Items]
Shares repurchased (in shares) | shares	7,780
Sabby Management, LLC [Member] | Series A Convertible Preferred Stock [Member]
Liquidity And Managements Plans [Line Items]
Maximum commitment under stock purchase agreement				$ 10,000,000
Number of closings | closing				2
Proceeds from sale of Series A preferred convertible stock		$ 5,000,000	$ 4,100,000
Expenses related stock issuance		$ 500,000	$ 400,000
Sabby Management, LLC [Member] | 2016 Sabby Purchase Agreement [Member]
Liquidity And Managements Plans [Line Items]
Payments for repurchase of private placement	$ 7,780,000
Shares converted on as-converted basis (in shares) | shares	4,205,405
Sabby Management, LLC [Member] | 2016 Sabby Purchase Agreement [Member] | Series A Convertible Preferred Stock [Member]
Liquidity And Managements Plans [Line Items]
Proceeds from sale of Series A preferred convertible stock	$ 5,600,000
Private Placement [Member] | Sabby Management, LLC [Member] | 2016 Sabby Purchase Agreement [Member]
Liquidity And Managements Plans [Line Items]
Fixed conversion price per share (in dollars per share) | $ / shares	$ 1.00
Private Placement [Member] | Sabby Management, LLC [Member] | 2016 Sabby Purchase Agreement [Member] | Series B Convertible Preferred Stock [Member]
Liquidity And Managements Plans [Line Items]
Maximum commitment under stock purchase agreement	$ 13,780,000
Number of shares issued in transaction (in shares) | shares	13,780
Number of closings | closing	2
Private Placement [Member] | Sabby Management, LLC [Member] | 2016 Sabby Purchase Agreement [Member] | Common Stock [Member]
Liquidity And Managements Plans [Line Items]
Shares issuable upon conversion (in shares) | shares	13,780,000
Aspire Capital Fund, LLC [Member]
Liquidity And Managements Plans [Line Items]
Maximum commitment under stock purchase agreement					$ 10,000,000.0
Agreement term					24 months
Number of shares issued in transaction (in shares) | shares										506,585
Proceeds from issuance of common stock										$ 1,400,000