Selected Quarterly Financial Data - Explanatory Information (Details) $ / shares in Units, $ in Millions			1 Months Ended	12 Months Ended
	Jul. 28, 2015 $ / shares shares	Jul. 10, 2015	Jul. 27, 2015 USD ($) $ / shares shares	Dec. 31, 2015 $ / shares shares
Series C preferred stock
Quarterly Financial Information [Line Items]
Public offering price (in dollars per share) | $ / shares				$ 5.00
Series C preferred stock | Series C Warrants Issued with Series C Redeemable Preferred Stock Financing
Quarterly Financial Information [Line Items]
Number of shares issued upon exercise of warrants			1,000,000
Exercise price of warrants (in dollars per share) | $ / shares			$ 5.00
Proceeds from exercise of warrants (in dollars) | $			$ 5
Common Stock
Quarterly Financial Information [Line Items]
Reverse stock split ratio		0.4167
Common Stock | Series C Warrants Issued with Series C Redeemable Preferred Stock Financing | Cashless exercise of redeemable convertible preferred stock warrant into common stock
Quarterly Financial Information [Line Items]
Shares issued on conversion	78,926
Common Stock | All series of redeemable convertible preferred stock | Conversion of redeemable convertible preferred stock into common stock
Quarterly Financial Information [Line Items]
Shares issued on conversion	9,217,983
Common Stock | IPO
Quarterly Financial Information [Line Items]
Net proceeds from issuance of common stock (in shares)	5,520,000			5,520,000
Public offering price (in dollars per share) | $ / shares	$ 15.00
Common Stock | Over-allotment option
Quarterly Financial Information [Line Items]
Net proceeds from issuance of common stock (in shares)	720,000