Stock-based Compensation - Summarizes Information About Stock Options Exercisable (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares
Number of Options Outstanding | shares	1,220,000
Options Outstanding Weighted-Average Remaining Contractual Life in Years	6 years
Options Outstanding Weighted-Average Exercise Price	$ 5.37
Options Exercisable Number Outstanding | shares	695,000
Options Exercisable Weighted-Average Exercise Price	$ 5.07
Aggregate Intrinsic Value Options Outstanding | $	$ 558,000
Aggregate Intrinsic Value Options Exercisable | $	$ 448,000
Weighted-Average Remaining Contractual Term, Options Outstanding at End of Period	6 years
Weighted-Average Remaining Contractual Term, Options Exercisable at End of Period	5 years
Exercise Price One [Member]
Options Outstanding Exercise Prices, Lower Range Limit	$ 2.06
Options Outstanding Exercise Prices, Upper Range Limit	$ 4.87
Number of Options Outstanding | shares	320,000
Options Outstanding Weighted-Average Remaining Contractual Life in Years	4 years
Options Outstanding Weighted-Average Exercise Price	$ 4.03
Options Exercisable Number Outstanding | shares	240,000
Options Exercisable Weighted-Average Exercise Price	$ 3.85
Exercise Price Two [Member]
Options Outstanding Exercise Prices, Lower Range Limit	4.88
Options Outstanding Exercise Prices, Upper Range Limit	$ 5.70
Number of Options Outstanding | shares	235,000
Options Outstanding Weighted-Average Remaining Contractual Life in Years	7 years
Options Outstanding Weighted-Average Exercise Price	$ 5.37
Options Exercisable Number Outstanding | shares	162,000
Options Exercisable Weighted-Average Exercise Price	$ 5.46
Exercise Price Three [Member]
Options Outstanding Exercise Prices, Lower Range Limit	5.71
Options Outstanding Exercise Prices, Upper Range Limit	$ 5.97
Number of Options Outstanding | shares	210,000
Options Outstanding Weighted-Average Remaining Contractual Life in Years	4 years
Options Outstanding Weighted-Average Exercise Price	$ 5.81
Options Exercisable Number Outstanding | shares	210,000
Options Exercisable Weighted-Average Exercise Price	$ 5.81
Exercise Price Four [Member]
Options Outstanding Exercise Prices, Lower Range Limit	5.98
Options Outstanding Exercise Prices, Upper Range Limit	$ 6.90
Number of Options Outstanding | shares	455,000
Options Outstanding Weighted-Average Remaining Contractual Life in Years	8 years
Options Outstanding Weighted-Average Exercise Price	$ 6.11
Options Exercisable Number Outstanding | shares	83,000
Options Exercisable Weighted-Average Exercise Price	$ 6.00