Stock-Based Compensation - Summary of Company's Stock Option Activity and Related Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Stock Options Outstanding
Number of Stock Options Outstanding, Beginning balance	11,165,846
Number of Stock Options Outstanding, Options granted	736,579
Number of Stock Options Outstanding, Options exercised	(20,579)
Number of Stock Options Outstanding, Options cancelled or forfeited	(3,739,498)
Number of Stock Options Outstanding, Ending balance	8,142,348	11,165,846
Number of Stock Options Outstanding, Options exercisable	5,319,817
Number of Stock Options Outstanding, Options vested and expected to vest	7,875,294
Weighted- Average Exercise Price
Weighted- Average Exercise Price, Beginning balance	$ 7.44
Weighted- Average Exercise Price, Options granted	1.97
Weighted- Average Exercise Price, Options exercised	0.72
Weighted- Average Exercise Price, Options cancelled or forfeited	6.95
Weighted- Average Exercise Price, Ending balance	7.14	$ 7.44
Weighted- Average Exercise Price, Options exercisable	7.20
Weighted- Average Exercise Price,Options vested and expected to vest	$ 7.18
Weighted- Average Remaining Contractual Life (Years)
Options Outstanding, Weighted- Average Remaining Contractual Life (Years)	7 years 3 months 18 days	7 years 7 months 6 days
Weighted- Average Remaining Contractual Life (Years), Options exercisable	6 years 9 months 18 days
Weighted- Average Remaining Contractual Life (Years), Options vested and expected to vest	7 years 2 months 12 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 2,638	$ 1,907
Aggregate Intrinsic Value, Options exercisable	1,354
Aggregate Intrinsic Value, Options vested and expected to vest	$ 2,438