Loan and Security Agreement (Details) $ / shares in Units, $ in Thousands				1 Months Ended	6 Months Ended
	Jul. 10, 2014 USD ($) $ / shares shares	Jun. 11, 2014 $ / shares shares	May. 30, 2014 USD ($) $ / shares shares	May. 31, 2014	Jun. 30, 2015 USD ($) item
Loan and Security Agreement
Maximum borrowing limit			$ 30,000
Future principal payments under the Credit Facility
2016					$ 10,000
2017					10,000
2018					5,000
Total					$ 25,000
Series B-2 Convertible Preferred Stock
Future principal payments under the Credit Facility
Number of shares that can be purchased for warrants issued | shares			10,258
Exercise price of warrant (in dollars per share) | $ / shares			$ 61.42
Series B-2 Convertible Preferred Stock | Maximum
Future principal payments under the Credit Facility
Share issue price (in dollars per share) | $ / shares		$ 8.00
Conversion of convertible preferred stock, and associated accumulated dividends into common stock (in shares) | shares		78,760
Initial Term Loan
Loan and Security Agreement
Aggregate principal amount			$ 21,000
Minimum aggregate net cash proceeds required to be received to make interest only payments			65,000
Future principal payments under the Credit Facility
Basis spread (as a percent)				9.85%
Variable interest rate, description				one-month LIBOR
Fair value of warrants issued (in dollars)			300
Payment of facility fees to lender			300
Payment of reimbursed costs to lender			$ 100
Debt discount amortization period			48 months
Second Term Loan
Future principal payments under the Credit Facility
Additional term loan that can be requested if threshold of IPO is met			$ 9,000
Threshold net cash proceed as prerequisite to request additional term loan			$ 65,000
Term Loan B
Loan and Security Agreement
Aggregate principal amount	$ 4,000
Number of payments of principal and interest payable monthly in arrears | item					30
Future principal payments under the Credit Facility
Number of shares that can be purchased for warrants issued | shares	4,706
Exercise price of warrant (in dollars per share) | $ / shares	$ 12.75
Expiration term of warrants	5 years
Fair value of warrants issued (in dollars)	$ 41