Stock-Based Compensation - Additional information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Granted (in shares)		291,100	158,918
Stock-based compensation expense		$ 1,658,000	$ 1,608,000
Assets	$ 455,000	455,000
Liabilities	455,000	455,000	$ 11,868,000
Stock option liability
Stock-Based Compensation
Liabilities	455,000	455,000
Deferred charge related to stock options
Stock-Based Compensation
Assets	455,000	$ 455,000
Options
Stock-Based Compensation
Granted (in shares)		351,516	138,662
Weighted-average grant date fair value (in dollars per share)		$ 9.89	$ 11.78
Total unrecognized compensation costs	3,704,000	$ 3,704,000
Total unrecognized compensation costs, period of recognition (in years)		2 years 10 months 24 days
Aggregate intrinsic value, based on the fair market value of the common stock of options outstanding	$ 1,556,000	$ 1,556,000
Aggregate intrinsic value, based on the fair market value of the common stock of options vested		1,186,000
Stock-based compensation expense		1,488,000	$ 1,303,000
Options | Number of shares excess granted under the 2014 Plan
Stock-Based Compensation
Granted (in shares)	76,417
Options | Stock option liability | Accrued liabilities | Number of shares excess granted under the 2014 Plan
Stock-Based Compensation
Liabilities	$ 455,000	455,000
Options | Deferred charge related to stock options | Prepaid expenses and other current assets | Number of shares excess granted under the 2014 Plan
Stock-Based Compensation
Assets	$ 455,000	$ 455,000
Options | Consultants
Stock-Based Compensation
Granted (in shares)		16,000	20,256
Stock-based compensation expense		$ 38,000	$ 173,000