XML 52 R41.htm IDEA: XBRL DOCUMENT v3.19.1
Stockholders’ Equity - Schedule of Valuation Assumptions (Details) - Common stock options
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Class of Stock [Line Items]    
Volatility 59.20% 56.00%
Risk-free interest rate 2.62% 2.40%
Expected life in years 6 years 2 months 1 day 6 years 2 months 23 days
Dividend yield rate 0.00% 0.00%