XML 82 R65.htm IDEA: XBRL DOCUMENT v3.22.0.1
Equity Incentive Plans - Valuation Assumptions for ESPP (Details) - ESPP
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term (years) 6 months 6 months 6 months
Expected volatility 123.00% 79.00% 69.00%
Risk-free interest rate 0.65% 0.48% 2.00%
Dividend yield 0.00% 0.00% 0.00%