Stock-Based Compensation - Employee Stock Purchase Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 07, 2017
Class of Stock
Proceeds from employee stock purchases	$ 59,000	$ 113,000	$ 121,000
Percentage of share-based compensation expense	15.00%
Weighted average grant date fair value of options granted during the period (per share)	$ 1.54	$ 1.25	$ 1.64
2017 Employee Stock Purchase Plan
Class of Stock
Maximum percentage of total combined voting power or value of the stock of the Company after the grant	5.00%
Common shares available for grant	196,225
Common stock share issued	49,117	75,999	60,953
Employee Stock Purchase Plan [Member]
Class of Stock
Minimum percentage in payroll of deduction base salary to acquire shares of common stock	1.00%
Maximum percentage in payroll of deduction base salary to acquire shares of common stock	10.00%
Percentage of fair market value of common stock for the ESPP option price	85.00%
Annual maximum a participant may purchase under the employee stock purchase plan	$ 25,000
Defined Contribution Plan, Cost	$ 100,000	$ 100,000	$ 100,000
Maximum [Member] | 2017 Employee Stock Purchase Plan
Class of Stock
Common stock shares authorized for issuance under stock purchase plan				412,500
Maximum [Member] | Employee Stock Purchase Plan [Member]
Class of Stock
Subsequent offering period as established by the compensation committee	12 months