Debt (Details) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	Jun. 30, 2014 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) item $ / shares	Sep. 30, 2015 USD ($)	Jul. 31, 2013 $ / shares shares
Estimated future principal payments due under the Credit Facility
Payments of long term debt				$ 1,193	$ 253
Warrant
Debt
Exercise price (in dollars per share) | $ / shares		$ 7.25		$ 7.25
Series A preferred stock warrant
Debt
Warrants exercisable into stock (in shares) | shares						1,940,000
Exercise price (in dollars per share) | $ / shares						$ 1.00
Credit Facility
Debt
Maximum borrowing capacity	$ 20,000
Percentage of final payment equal to amount drawn under the Credit Facility				8.00%
Number of financial covenants associated to the Credit Facility | item				0
Estimated future principal payments due under the Credit Facility
2016		$ 411		$ 411
2017		1,709		1,709
2018		1,049		1,049
Total		3,169		3,169
Interest expense		100	$ 100	300	400
Interest payments		100	$ 100	200	$ 200
Term A Loan
Debt
Maximum borrowing capacity	$ 5,000
Period of consecutive equal monthly installments of principal and interest	36 months
Interest rate (as a percent)	6.40%
Debt issuance costs	$ 100
Term A Loan | Warrant
Debt
Warrants exercisable into stock (in shares) | shares	8,230
Exercise price (in dollars per share) | $ / shares	$ 15.19
Unamortized discount	$ 100
Term A Loan | Warrant | Maximum
Debt
Unamortized discount		100		100
Debt issuance costs		$ 100		$ 100
Term A Loan | Secured promissory notes
Debt
Proceeds from issuance of debt	5,000
Term B Loan
Debt
Maximum borrowing capacity	15,000
Remaining borrowing capacity	$ 15,000