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Stock-Based Compensation - Additional Information (Details) - USD ($)		12 Months Ended
	Oct. 07, 2016	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation
Total grant date fair value of options vested		$ 2,200,000	$ 2,300,000
Weighted-average grant date fair value of options granted		$ 1.81	$ 4.06
Shares available for future issuance (in shares)		179,219	638,227
Value of share issued		$ 1,595,000	$ 282,000
Weighted-average exercise price (per share)		$ 5.58	$ 7.17
Number of stock options granted (in shares)		894,955
Options remained outstanding		2,272,905	1,931,903
2016 Employee Incentive Plan
Share-based Compensation
Maximum number of common stock shares may be issued under the plan	500,000
Annual increases in the number of shares available for issuance, percentage of outstanding capital stock	3.00%
2008 Equity Incentive Plan
Share-based Compensation
Vesting period		4 years
Exercise period		10 years
Number of stock options granted (in shares)		0
Options remained outstanding		157,329
2008 Equity Incentive Plan \| Incentive Stock Options \| Minimum
Share-based Compensation
Percentage of exercise price of fair market value of stock at the date of grant		100.00%
2008 Equity Incentive Plan \| Incentive Stock Options \| Maximum
Share-based Compensation
Percentage of exercise price of fair market value of stock at the date of grant		110.00%
2016 Employee Stock Purchase Plan
Share-based Compensation
Shares available for future issuance (in shares)		526,863
Value of share issued		$ 112,000	$ 232,000
Number of shares issued (in shares)		49,951	44,344