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Stock Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands |  |  | 12 Months Ended |
--- | --- | --- | --- | ---
Jun. 11, 2020 | Jun. 13, 2018 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] |  |  |  |  |
Number of common stock available for future grant |  |  | 1,255,302 |  |
Shares remaining outstanding |  |  | 2,355,615 | 1,577,541 | 1,361,977
Total stock-based compensation |  |  | $ 3,627 | $ 3,204 |
Employee Stock Option |  |  |  |  |
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] |  |  |  |  |
Unrecognized employee stock based compensation expense |  |  | $ 6,500 |  |
Unrecognized employee stock based compensation expense, period for recognition |  |  | 2 years 7 months 17 days |  |
2018 Omnibus Incentive Plan |  |  |  |  |
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] |  |  |  |  |
Increase in number of shares of common stock reserved for issuance | 1,300,000 |  |  |  |
Common Stock, Capital Shares Reserved for Future Issuance | 2,800,000 |  |  |  |
2018 Employee Stock Purchase Plan |  |  |  |  |
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] |  |  |  |  |
Number of common stock available for future grant |  |  | 300,444 |  |
Maximum employee subscription rate |  | 15.00% |  |  |
Number of common stock authorized for issuance |  |  | 359,545 |  |
Number of common stock stock issued |  |  | 38,248 |  |
Proceeds from Issuance |  |  | $ 200 |  |
Total stock-based compensation |  |  | $ 100 | $ 100 |
2018 Employee Stock Purchase Plan | Maximum |  |  |  |  |
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] |  |  |  |  |
Percentage of fair market value of common stock |  | 85.00% |  |  |

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- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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