Stockholders' Equity - Activity of Stock Option by Exercise Price Range (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of exercise prices, lower range (in dollars per share)	$ 1.18	$ 0.61
Range of exercise prices, upper range (in dollars per share)	$ 7.37	$ 6.55
Options outstanding (in shares)	3,160,397	3,108,868	2,714,561
Options outstanding, weighted average exercise price (in dollars per share)	$ 2.72	$ 2.26	$ 1.88
Options exercisable (in shares)	1,835,799	1,986,740	2,590,030
Weighted average exercise price of options exercisable (in dollars per share)	$ 2.28	$ 1.81	$ 1.89
Total Intrinsic Value of Options Exercised	$ 1,641,687	$ 112,213
Total Fair Value of Options Vested	$ 3,267,672	$ 2,980,110
$0.61 - 6.55
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding (in shares)		3,108,868
Options outstanding, weighted average remaining life in years		5 years 8 months 20 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 2.26
Options exercisable (in shares)		1,986,740
Options exercisable, weighted average remaining life in years		3 years 5 months 16 days
Weighted average exercise price of options exercisable (in dollars per share)		$ 1.81
$1.18 - 7.37
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding (in shares)	3,160,397
Options outstanding, weighted average remaining life in years	6 years 2 months 27 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 2.72
Options exercisable (in shares)	1,835,799
Options exercisable, weighted average remaining life in years	4 years 3 months 18 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 2.28