Warrants - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
|
Class Of Warrant Or Right [Line Items] | ||||
Purchase of common stock warrants exercised | 24,000 | 445,000 | 94,000 | 468,000 |
Proceeds from exercise of warrants | $ 500 | $ 105 | $ 524 | |
Exercise of warrants | 40,000 | 96,000 | ||
Shares issued | 15,000 | 40,000 | ||
Maximum [Member] | ||||
Class Of Warrant Or Right [Line Items] | ||||
Proceeds from exercise of warrants | $ 100 |