Stockholders' Equity (Details) - Stock Option [Member] - USD ($)		6 Months Ended	12 Months Ended
		Jun. 30, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Exercise Price, Outstanding, Beginning		$ 6.37	$ 4.58
Weighted Average Exercise Price, Grants		7.03	7.38
Weighted Average Exercise Price, Terminations		5.65	6.63
Weighted Average Exercise Price, Exercises		4.80	1.89
Weighted Average Exercise Price, Outstanding, Ending		6.51	$ 6.37
Weighted Average Exercise Price, Vested		5.67
Weighted average exercise price, Vested and expected to vest		$ 6.51
Aggregate Intrinsic Value, Outstanding, Beginning	[1]	$ 266,020	$ 1,513,980
Aggregate Intrinsic Value, Outstanding, Ending	[1]	(3,920)	$ 266,020
Aggregate Intrinsic Value, Vested	[1]	63,150
Aggregate Intrinsic Value, Vested and expected to vest	[1]	$ (3,920)
2000 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Beginning balance		12,500	117,500
Grants
Terminations
Exercises			(105,000)
Outstanding, Ending balance		12,500	12,500
Vested		12,500
Vested and expected to vest		12,500
Reserved for future grants
2010 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Beginning balance		270,000	242,500
Grants		10,000	48,500
Terminations		(20,000)	(19,000)
Exercises		(15,000)	(2,000)
Outstanding, Ending balance		245,000	270,000
Vested		63,500
Vested and expected to vest		245,000
Reserved for future grants		11,000
2017 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Beginning balance		111,500
Grants		10,000	122,500
Terminations			(11,000)
Exercises
Outstanding, Ending balance		121,500	111,500
Vested
Vested and expected to vest		121,500
Reserved for future grants		178,500

[1] Intrinsic value is the difference between the fair market value as of the date indicated and as of the date of the option grant.