Stock-based Compensation - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	May 31, 2015
Stock-based compensation
Shares of common stock authorized for issuance outstanding (in shares)	3,592,233		3,037,690
Employee Stock Purchase Plan, Purchase Price Percentage	85.00%
Issuance for employee stock purchase plan, shares	50,151
Proceeds from issuances of common stock from employee stock purchase plans	$ 510,000	$ 673,000
Employee Stock Purchase Plan, Compensation Expense	122,000	$ 106,000
Restricted Stock Awards And Restricted Stock Units
Stock-based compensation
Unrecognized compensation cost related to outstanding options	$ 33,065
Period over which unrecognized compensation cost is expected to be recognized as expense	3 years 2 months 12 days
2014 Stock Incentive Plan
Stock-based compensation
Shares of common stock authorized for issuance (in shares)				2,700,000
Shares of common stock remaining available for future grant	1,395,405
Increase in number of authorized shares on the first day of each fiscal year, as a percentage of outstanding common stock (as a percent)	4.00%
Vesting period	4 years
Contractual life	10 years
2014 Stock Incentive Plan | Minimum
Stock-based compensation
Period following termination date vested options are exercisable	1 month
2014 Stock Incentive Plan | Maximum
Stock-based compensation
Period following termination date vested options are exercisable	3 months