Notes Payable - Additional Information (Detail) - Comerica [Member] - USD ($)			6 Months Ended	12 Months Ended		16 Months Ended
	Sep. 17, 2015	Sep. 09, 2013	Aug. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2014
Debt Instrument [Line Items]
Additional interest expense				$ 96,000	$ 66,000
Unamortized debt discount				0	96,000	$ 96,000
Loan and Security Agreement [Member]
Debt Instrument [Line Items]
Borrowings amount		$ 3,000,000
Amount received from borrowings		$ 1,000,000	$ 2,000,000			$ 3,000,000
Principal repayments amount				900,000	$ 400,000
Payments of Debt	$ 1,765,000
Extinguishment amount of outstanding principal	1,700,000
Final fees and accrued interest	$ 65,000
Loss on extinguishment debt				$ 140,000