Convertible Notes - Related Parties - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Interest expense related to accrued interest and amortization of debt discount			$ 0	$ 1,500
Series F Convertible Preferred Stock
Debt Instrument [Line Items]
Convertible notes, shares issued upon conversion	1,511,723
Convertible preferred stock, warrants issued	372,045
Convertible Notes
Debt Instrument [Line Items]
Aggregate principal amount of convertible promissory notes issued and sold	$ 1,900
Convertible notes, accrued interest	$ 30	$ 30
Existing Stockholders | Convertible Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount of convertible promissory notes issued and sold		$ 1,900
Convertible debt interest rate	12.00%	12.00%
Debt instrument maturity period	1 year