Liquidity - Offering (Details) - USD ($)		3 Months Ended	6 Months Ended
	Mar. 23, 2016	Jun. 30, 2016	Jun. 30, 2016
Recent Significant Transaction
Proceeds from issuance of common stock, net of issuance costs			$ 45,738,000
Offering
Recent Significant Transaction
Shares issued	15,800,000
Price per share (in dollars per share)	$ 2.85
IPO and Underwriters' Option
Recent Significant Transaction
Shares issued		17,239,143
Proceeds from issuance of common stock, net of issuance costs		$ 44,800,000
Underwriters' discounts and commissions		2,700,000
Additional offering related costs		1,400,000
Amended and Restated Loan and Security Agreement
Recent Significant Transaction
Potential maximum borrowing capacity		$ 30,000,000	$ 30,000,000