Annual report pursuant to Section 13 and 15(d)

Options Outstanding and Exercisable (Detail)

v3.21.1
Options Outstanding and Exercisable (Detail)
shares in Thousands
 12 Months Ended
Dec. 31, 2020
$ / shares
shares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Options Outstanding Number of Shares | shares 2,398
Options Outstanding Weighted Average Exercise Price Per Share $ 2.96
Options Outstanding Weighted Average Remaining Life (Years) 7 years 2 months 12 days
Options Exercisable Number of Shares | shares 1,074
Options Exercisable Weighted Average Exercise Price Per Share $ 6.05
$0.29 - $0.33  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 0.29
Range of Exercise Prices, Upper Limit $ 0.33
Options Outstanding Number of Shares | shares 20
Options Outstanding Weighted Average Exercise Price Per Share $ 0.29
Options Outstanding Weighted Average Remaining Life (Years) 10 years
$0.34 - $0.48  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 0.34
Range of Exercise Prices, Upper Limit $ 0.48
Options Outstanding Number of Shares | shares 1,222
Options Outstanding Weighted Average Exercise Price Per Share $ 0.38
Options Outstanding Weighted Average Remaining Life (Years) 9 years 4 months 24 days
$0.49 - $2.32  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit $ 0.49
Range of Exercise Prices, Upper Limit $ 2.32
Options Outstanding Number of Shares | shares 390
Options Outstanding Weighted Average Exercise Price Per Share $ 1.81
Options Outstanding Weighted Average Remaining Life (Years) 7 years 7 months 6 days
Options Exercisable Number of Shares | shares 310
Options Exercisable Weighted Average Exercise Price Per Share $ 1.89
$2.33 - $7.23  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 2.33
Range of Exercise Prices, Upper Limit $ 7.23
Options Outstanding Number of Shares | shares 320
Options Outstanding Weighted Average Exercise Price Per Share $ 5.52
Options Outstanding Weighted Average Remaining Life (Years) 4 years 1 month 6 days
Options Exercisable Number of Shares | shares 318
Options Exercisable Weighted Average Exercise Price Per Share $ 5.52
$7.24 - $13.20  
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]  
Range of Exercise Prices, Lower Limit 7.24
Range of Exercise Prices, Upper Limit $ 13.20
Options Outstanding Number of Shares | shares 446
Options Outstanding Weighted Average Exercise Price Per Share $ 9.31
Options Outstanding Weighted Average Remaining Life (Years) 2 years 9 months 18 days
Options Exercisable Number of Shares | shares 446
Options Exercisable Weighted Average Exercise Price Per Share $ 9.31