XML 61 R45.htm IDEA: XBRL DOCUMENT v3.6.0.2
Summary of Significant Accounting Policies - Stock-Based Compensation (Details) - Stock Options
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Employees and Directors      
Summary of assumptions used to estimate the fair value of stock options      
Risk-free interest rate 0.91% 0.99% 1.47%
Expected volatility 76.00% 74.00% 109.00%
Expected life in years 5 years 5 years 5 years
Dividend yield 0.00% 0.00% 0.00%
Forfeiture rate 7.00% 7.00% 8.00%
Non Employee      
Summary of assumptions used to estimate the fair value of stock options      
Risk-free interest rate (minimum) 2.30% 2.10% 1.50%
Risk-free interest rate (maximum) 2.50% 2.30% 2.70%
Dividend yield 0.00% 0.00% 0.00%
Non Employee | Minimum      
Summary of assumptions used to estimate the fair value of stock options      
Expected volatility 71.00% 105.00% 104.00%
Expected life in years 7 years 7 years 7 years
Non Employee | Maximum      
Summary of assumptions used to estimate the fair value of stock options      
Expected volatility 104.00% 108.00% 115.00%
Expected life in years 10 years 10 years 10 years