Preferred Stock, Common Stock and Stockholders' Equity - Equity Incentive Award Plans - Additional Information (Detail)		6 Months Ended	12 Months Ended
	Apr. 26, 2018 shares	Jun. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares	Jan. 01, 2021 shares
Sale Of Stock [Line Items]
Aggregate number of shares of common stock reserved under the plan	6,286,425		7,566,145	7,678,152
Award plan expiration month and year	2028-02
Stockholders' equity, stock split, conversion ratio		0.75
Stock options exchanged		2,456,999
Stock options issued		1,842,746
Exercise price | $ / shares		$ 0.62
Share-based compensation expense | $		$ 84,000
Share-based compensation arrangement, vesting period		4 years
Options available for future grant			1,402,433	1,587,155
Options granted, weighted average term			10 years
Number of stock options granted			1,172,000	829,500
Intrinsic value, common stock price | $ / shares			$ 2.58	$ 1.62
Weighted Average Grant Date Fair Value Per Share, Granted | $ / shares			$ 1.23	$ 0.91
Minimum [Member]
Sale Of Stock [Line Items]
Share-based compensation arrangement, vesting period			1 year
Maximum [Member]
Sale Of Stock [Line Items]
Share-based compensation arrangement, vesting period			4 years
Amended and Restated Equity Incentive Plan 2013 [Member]
Sale Of Stock [Line Items]
Aggregate number of shares of common stock reserved under the plan	8,000,000
Shares available for issuance, description			In addition, the number of shares available for issuance is annually increased on the first day of each fiscal year by that number of shares equal to the least of (a) four percent of the outstanding shares of common stock on the last day of the immediately preceding calendar year, and (b) such other amount determined by the Company’s board of directors. Notwithstanding the foregoing, the number of shares of common stock that may be issued or transferred pursuant to incentive stock options under the Restated Plan may not exceed an aggregate of 8,000,000 shares.
Amended and Restated Equity Incentive Plan 2013 [Member] | Annual Increase in Shares [Member]
Sale Of Stock [Line Items]
Reserve percentage for issuance of shares	4.00%
2013 Equity Incentive Award Plan [Member]
Sale Of Stock [Line Items]
Additional common stock reserved for issuance			4,073,526
Options available for future grant			1,402,433
2013 Equity Incentive Award Plan [Member] | Subsequent Event [Member]
Sale Of Stock [Line Items]
Aggregate number of shares of common stock reserved under the plan					1,064,878
Options available for future grant					2,467,311