Equity Incentive Plan - Options Rollforward (Details) - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]      
Balance at beginning of period 528,750 445,417  
Granted 37,500 425,000  
Forfeited or cancelled (42,500) (341,667)  
Balance at end of period 523,750 528,750 445,417
Non-exercisable (148,333) (288,750)  
Outstanding and exercisable at end of period 375,417 240,000  
Granted, grant date fair value $ 0.58 $ 0.78  
Weighted Average Price      
Weighted average exercise price, beginning 9.57 26.20  
Granted, weighted average exercise price 4.00 4.00  
Forfeited or cancelled, weighted average exercise price 4.00 24.12  
Weighted average exercise price, ending 9.63 9.57 $ 26.20
Non-exercisable, weighted average price 4.00 4.00  
Outstanding and exercisable, weighted average price $ 11.85 $ 16.28  
Weighted Average Remaining Contractual Term      
Weighted average remaining contractual term, outstanding 7 years 2 months 12 days 8 years 1 month 6 days 6 years 10 months 24 days
Weighted average remaining contractual term, granted 8 years 4 months 24 days 8 years 7 months 6 days  
Weighted average remaining contractual term, forfeited or cancelled 7 years 8 months 12 days 6 years 9 months 18 days  
Weighted average remaining contractual term, non-exercisable 8 years 3 months 18 days 8 years 10 months 24 days  
Weighted average remaining contractual term, exercisable 6 years 8 months 12 days 7 years 2 months 12 days