Quarterly report pursuant to Section 13 or 15(d)

Subsequent events (Details Textual)

v3.7.0.1
Subsequent events (Details Textual) - USD ($)
1 Months Ended
Jul. 27, 2017
Jun. 30, 2017
Series A Warrants [Member]    
Subsequent Event [Line Items]    
Class of Warrant or Right, Exercise Price of Warrants or Rights   $ 4.85
Subsequent Event [Member] | Horizon Technology Finance Corporation [Member]    
Subsequent Event [Line Items]    
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 1.96  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights 280,612  
Class of Warrant or Right, Terms 18 months  
Subsequent Event [Member] | Venture Loan [Member]    
Subsequent Event [Line Items]    
Debt Instrument, Final Payment on Each Loan Tranche,Percentage 5.00%  
Subsequent Event [Member] | Venture Loan [Member] | Horizon Technology Finance Corporation [Member]    
Subsequent Event [Line Items]    
Debt Instrument, Face Amount $ 7,000,000  
Debt Instrument, Maturity Date Dec. 31, 2018  
Debt Instrument, Description of Variable Rate Basis one-month LIBOR (floor of 1.10%) plus 8.40%  
Debt Instrument, Payment Terms In addition, if we repay all or a portion of the loan prior to the applicable maturity date, we will pay Horizon a prepayment penalty fee, based on a percentage of the then outstanding principal balance, equal to 4% if the prepayment occurs during the interest-only payment period, 3% if the prepayment occurs during the 12 months following such period, and 2% thereafter.  
Debt Instrument, Debt Default, Description of Violation or Event of Default default interest rate of an additional 5% may be applied to the outstanding loan balances  
Debt Instrument, Additional Face Amount $ 3,000,000  
Subsequent Event [Member] | Minimum [Member] | Horizon Technology Finance Corporation [Member]    
Subsequent Event [Line Items]    
Capitalization, Long-term Debt and Equity 50,000,000  
Royalty Revenue 750,000  
Subsequent Event [Member] | Minimum [Member] | Venture Loan [Member] | Horizon Technology Finance Corporation [Member]    
Subsequent Event [Line Items]    
Debt Instrument, Face Amount $ 10,000,000  
Subsequent Event [Member] | Series A Warrants [Member] | Maximum [Member]    
Subsequent Event [Line Items]    
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 4.89  
Subsequent Event [Member] | Series A Warrants [Member] | Minimum [Member]    
Subsequent Event [Line Items]    
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 4.85