Stockholders' Equity - Options Outstanding and Exercisable (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	248,512
Weighted Average Remaining Contractual Life (in years)	7 years 9 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 5.76
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	110,476
Weighted Average Remaining Contractual Life (in years)	6 years 1 month 6 days
Weighted Average Exercise Price (in dollars per share)	$ 8.63
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)	2.30
Range of Exercise Prices, upper limit (in dollars per share)	$ 3.25
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	59,558
Weighted Average Remaining Contractual Life (in years)	9 years 1 month 6 days
Weighted Average Exercise Price (in dollars per share)	$ 3.04
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	2,000
Weighted Average Remaining Contractual Life (in years)	4 years 10 months 24 days
Weighted Average Exercise Price (in dollars per share)	$ 2.45
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)	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)	9 years 2 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 3.43
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	0
Weighted Average Remaining Contractual Life (in years)	9 years 2 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 3.43
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)	4.01
Range of Exercise Prices, upper limit (in dollars per share)	$ 5.50
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	51,919
Weighted Average Remaining Contractual Life (in years)	6 years 7 months 6 days
Weighted Average Exercise Price (in dollars per share)	$ 4.96
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	50,461
Weighted Average Remaining Contractual Life (in years)	6 years 7 months 6 days
Weighted Average Exercise Price (in dollars per share)	$ 4.94
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)	5.51
Range of Exercise Prices, upper limit (in dollars per share)	$ 20.00
OPTIONS OUTSTANDING
Number of Shares Outstanding (in shares) | shares	62,870
Weighted Average Remaining Contractual Life (in years)	6 years
Weighted Average Exercise Price (in dollars per share)	$ 11.75
OPTIONS EXERCISABLE
Number of Shares Exercisable (in shares) | shares	58,015
Weighted Average Remaining Contractual Life (in years)	5 years 9 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 12.05