Quarterly report pursuant to Section 13 or 15(d)

Stock-based compensation - Summary of Status of Company's Restricted Stock Option Activity (Details)

v3.8.0.1
Stock-based compensation - Summary of Status of Company's Restricted Stock Option Activity (Details) - $ / shares
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2017
Number of Shares    
Granted (in shares) 0 960,000
Cancelled, expired, or forfeited (in shares)   (674,977)
Weighted Average Exercise Price    
Beginning balance (in dollars per share)   $ 4.28
Granted (in dollars per share)   2.13
Cancelled, expired, or forfeited (in dollars per share)   3.24
Ending balance (in dollars per share) $ 3.65 $ 3.65
Restricted Stock    
Number of Shares    
Beginning balance (in shares)   716,250
Granted (in shares)   410,000
Vested (in shares)   (81,750)
Cancelled, expired, or forfeited (in shares)   (169,500)
Ending balance (in shares) 875,000 875,000
Weighted Average Exercise Price    
Beginning balance (in dollars per share)   $ 2.73
Granted (in dollars per share)   2.13
Vested (in dollars per share)   2.73
Cancelled, expired, or forfeited (in dollars per share)   2.73
Ending balance (in dollars per share) $ 2.45 $ 2.45