Debt and Related Warrants - Warrants - Additional Information (Details) - USD ($)	1 Months Ended		12 Months Ended
	Jun. 30, 2015	Feb. 28, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 07, 2016	Dec. 31, 2010
Warrants
Loss from remeasurement			$ (372,000)	$ (15,000)	$ (6,000)
2015 Credit Facility
Warrants
Fair value of warrants	$ 48,900
SVB Credit Facility
Warrants
Fair value of warrants							$ 1,600
Warrants to Purchase Series A Redeemable Convertible Preferred Stock | SVB Credit Facility
Warrants
Number of shares the warrant can be converted to							3,076
Warrant exercise price							$ 26.00
Debt discount							$ 63,000
Warrants to Purchase Series B Redeemable Convertible Preferred Stock | 2015 Credit Facility
Warrants
Number of shares the warrant can be converted to	18,461
Warrant exercise price	$ 26.00
Fair value of warrants	$ 307,000			$ 307,000
Warrant exercise expiration period	10 years
Warrants to Purchase Series B Redeemable Convertible Preferred Stock | SVB Credit Facility
Warrants
Number of shares the warrant can be converted to		6,153
Warrant exercise price		$ 26.00
Fair value of warrants	$ 14,900	$ 106,000
Warrant exercise expiration period		10 years
Common Stock | Warrants to Purchase Series A Redeemable Convertible Preferred Stock | SVB Credit Facility
Warrants
Number of shares the warrant can be converted to						3,076
Common Stock | Warrants to Purchase Series B Redeemable Convertible Preferred Stock | SVB Credit Facility
Warrants
Number of shares the warrant can be converted to						6,153