XML 35 R73.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Stock-Based Compensation - Valuation Assumptions (Details)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Share-based Payment Arrangement [Abstract]    
Expected volatility 71.05% 67.13%
Expected life (years) 2 years 2 years 8 months 12 days
Risk-free interest rate 1.63% 2.55%