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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%