Stockholders' Equity - Options Outstanding and Exercisable (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	292,871
Weighted Average Remaining Contractual Life (in years)	7 years 3 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 3.78
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	159,007
Weighted Average Remaining Contractual Life (in years)	5 years 9 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 4.98
Exercise price, range one
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit (in dollars per share)	1.81
Range of Exercise Prices, upper limit (in dollars per share)	$ 2.29
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	75,711
Weighted Average Remaining Contractual Life (in years)	9 years 4 months 24 days
Weighted Average Exercise Price (in dollars per share)	$ 1.81
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	0
Weighted Average Remaining Contractual Life (in years)	0 years
Weighted Average Exercise Price (in dollars per share)	$ 0.00
Exercise price, range two
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit (in dollars per share)	2.30
Range of Exercise Prices, upper limit (in dollars per share)	$ 3.25
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	76,157
Weighted Average Remaining Contractual Life (in years)	6 years 2 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 2.86
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	47,135
Weighted Average Remaining Contractual Life (in years)	4 years 8 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 2.98
Exercise price, range three
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit (in dollars per share)	3.26
Range of Exercise Prices, upper limit (in dollars per share)	$ 4.00
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	74,165
Weighted Average Remaining Contractual Life (in years)	8 years 2 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 3.43
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	45,323
Weighted Average Remaining Contractual Life (in years)	8 years 2 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 3.43
Exercise price, range four
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit (in dollars per share)	4.01
Range of Exercise Prices, upper limit (in dollars per share)	$ 15.08
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	66,838
Weighted Average Remaining Contractual Life (in years)	5 years
Weighted Average Exercise Price (in dollars per share)	$ 7.46
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	66,549
Weighted Average Remaining Contractual Life (in years)	5 years
Weighted Average Exercise Price (in dollars per share)	$ 7.46