Debt (Details) $ / shares in Units, $ in Thousands					1 Months Ended	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014 USD ($) loan $ / shares shares	Apr. 15, 2014 USD ($) $ / shares shares	Mar. 10, 2014 USD ($) shares	Apr. 30, 2014 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	May. 29, 2015 USD ($)	Oct. 01, 2014 USD ($)	Mar. 31, 2014 $ / shares shares
Debt
Shares reserved for future issuances | shares						4,473,256,000	4,744,399,000
Short-term Debt						$ 14,833
Long-term debt obligation							$ 7,269
Series B Convertible Preferred Stock
Debt
Number of shares issued upon conversion of debt | shares					3,947,363		3,947,363
Series A Preferred Stock Or Qualified Financing Securities Warrants Exercise Price Dollars 0.01 | Series B Convertible Preferred Stock
Debt
Number of shares issuable upon exercise of warrants | shares										787,402
Convertible Debt Issued 2013
Debt
Outstanding principal amount converted				$ 12,500
Outstanding interest amount converted				$ 684
Convertible Debt Issued 2013 | Series A Convertible Preferred Stock
Debt
Number of shares issued upon conversion of debt | shares				13,184,383
Convertible Debt Issued 2014
Debt
Proceeds received from debt issuance				$ 5,000
Interest rate (as a percent)				8.00%
Warrant coverage (as a percent)				20.00%
Outstanding principal amount converted			$ 5,000		$ 5,000
Outstanding interest amount converted			$ 13		$ 13
Convertible Debt Issued 2014 | Series B Convertible Preferred Stock
Debt
Number of shares issued upon conversion of debt | shares			3,947,363
Exercise Price (in dollars per share) | $ / shares										$ 0.01
Convertible Debt Issued 2014 | Series A Preferred Stock Or Qualified Financing Securities Warrants Exercise Price Dollars 0.01 | Series B Convertible Preferred Stock
Debt
Number of shares issuable upon exercise of warrants | shares			787,402
Exercise Price (in dollars per share) | $ / shares			$ 0.01
Hercules Notes
Debt
Number of term loans | loan		2
Aggregate principal amount		$ 15,000
Percentage of prepayment fees		2.00%
Amount of prepayment fees, in case loan is repaid after 18 months		$ 0
Right to participate in sales and issuance of equity						1,000
Number of shares issuable upon exercise of warrants | shares		64,194
Exercise Price (in dollars per share) | $ / shares		$ 7.01
Outstanding borrowings		$ 2,000				15,000
Percentage of common stock price above warrant exercise price		15.00%
Shares reserved for future issuances | shares		248,093
Common stock fixed price above warrant exercise price | $ / shares		$ 8.06
Short-term Debt						14,833
Unamortized Debt Discount						167
Amortization of the debt discount included in interest expense						$ 89	$ 14
Hercules Notes | Minimum
Debt
Interest rate (as a percent)						7.95%
Hercules Notes | Prime Rate | Minimum
Debt
Interest rate (as a percent)						7.95%
Applicable margin ( as a percent)						3.25%
Base rate						Prime Rate
Hercules Term Loan One
Debt
Aggregate principal amount									$ 7,500
Number of monthly repayment installments	18 months
Hercules Term Loan Two
Debt
Aggregate principal amount								$ 7,500