Stock-Based Awards - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		6 Months Ended
	Jan. 01, 2020	Jan. 01, 2019	Jun. 16, 2017	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted						1,771,000
Options granted, weighted average exercise price per share						$ 0.72
Weighted average grant-date fair value of stock options						$ 0.48	$ 1.11
Aggregate fair value of stock options vested						$ 1,173	$ 1,142
Aggregate intrinsic value of stock options exercised						0	109
Recognized stock-based compensation expense				$ 560	$ 460	1,065	1,023
Aggregate unrecognized stock-based compensation expense				2,925		$ 2,925
Unrecognized stock-based compensation expense, weighted average period expects for recognition						2 years 4 months 24 days
Performance-based Awards [[Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense				$ 111	$ 23	$ 160	$ 23
2017 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted vesting period						4 years
Number of shares, available for grant				5,319,537		5,319,537
Number of shares remained available for grant				358,416		358,416
Stock reserved for future issuance				1,244,816		1,244,816
Maximum annual increase in common stock reserved for future issuance						1,244,816
Percentage of common stock shares outstanding						4.00%
Increase to shares authorized for issuance	1,112,414	589,939
Options granted						1,771,000
Options granted, weighted average exercise price per share						$ 0.72
2016 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted vesting period						4 years
Stock option expiration period						10 years
Number of shares, available for grant				0		0
2016 Stock Incentive Plan [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock reserved for future issuance				424,601		424,601
2017 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, available for grant				0		0
Stock reserved for future issuance			150,000
Maximum annual increase in common stock reserved for future issuance			622,408
Percentage of common stock shares outstanding			1.00%
Increase to shares authorized for issuance	0	0
Stock incentive plan description						On June 16, 2017, the Company’s stockholders approved the 2017 Employee Stock Purchase Plan (the “2017 ESPP”), which became effective on June 28, 2017. A total of 150,000 shares of common stock were initially reserved for issuance under this plan. Under the 2017 ESPP, the number of shares of common stock that may be issued under the 2017 ESPP will automatically increase on each January 1, beginning with the fiscal year ending December 31, 2018 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027, equal to the least of (i) 622,408 shares, (ii) 1% of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. The compensation committee of the board of directors has determined that the number of shares of common stock that may be issued under the 2017 ESPP would not be increased on January 1, 2019 or January 1, 2020. The Company has not issued any shares under the 2017 ESPP.
2006 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted vesting period						4 years
Stock option expiration period						10 years
Number of shares, available for grant				0		0
Stock incentive plan termination year						2016
Maximum [Member] | 2017 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted vesting period						4 years
Stock option expiration period						10 years
Maximum [Member] | 2006 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted vesting period						4 years