Preferred Stock, Common Stock and Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding beginning balance	4,077,259
Options, Granted	1,682,000	1,172,000
Options, Outstanding ending balance	5,013,459	4,077,259
2013 Equity Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding beginning balance	4,077,259
Options, Granted	1,682,000
Options, Exercised	(67,426)
Options, Expired/Forfeited/Exchanged	(678,374)
Options, Outstanding ending balance	5,013,459	4,077,259
Options, Vested and expected to vest at December 31, 2021	5,024,473
Options, Exercisable at December 31, 2021	2,580,048
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Outstanding beginning balance	$ 1.70
Weighted Average Exercise Price, Granted	2.42
Weighted Average Exercise Price, Exercised	0.67
Weighted Average Exercise Price, Expired/Forfeited/Exchanged	2.85
Weighted Average Exercise Price, Outstanding ending balance	1.80	$ 1.70
Weighted Average Exercise Price, Vested and expected to vest at December 31, 2021	1.80
Weighted Average Exercise Price, Exercisable at December 31, 2021	$ 1.83
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Remaining Contractual Term [Abstract]
Weighted Average Remaining Contractual Term (Years), Outstanding	7 years 10 months 6 days	8 years 1 month 2 days
Weighted Average Remaining Contractual Term (Years), Granted	9 years 1 month 17 days
Weighted Average Remaining Contractual Term (Years), Exercised	7 years 4 months 20 days
Weighted Average Remaining Contractual Term (Years), Expired/Forfeited/Exchanged	6 years 6 months 14 days
Weighted Average Remaining Contractual Term (Years), Vested and expected to vest at December 31, 2021	7 years 10 months 6 days
Weighted Average Remaining Contractual Term (Years), Exercisable at December 31, 2021	7 years 3 months 7 days
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Aggregate Intrinsic Value [Abstract]
Aggregate Intrinsic Value, Outstanding beginning balance	$ 5,134,768
Aggregate Intrinsic Value, Exercised	43,715
Aggregate Intrinsic Value, Expired/Forfeited/Exchanged	$ 3,923
Aggregate Intrinsic Value, Outstanding ending balance		$ 5,134,768