Basis of Presentation - Impact on Financial Results from Adopting Revenue Recognition Standard (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product revenue	$ 1,007,915	$ 2,129,125	$ 3,925,504	$ 6,549,832
Support and services revenue	3,052,246	3,976,308	9,140,187	12,329,042
Selling and marketing	1,144,271	1,128,850	3,209,930	5,288,991
Income tax expense (benefit)	(96,858)	(9,896)	(33,868)	207,352
Net income (loss)	(332,429)	1,429,173	(829,656)	(322,825)
Net income attributable to common stockholders	$ (686,444)	$ 1,214,173	$ (4,026,593)	$ (957,489)
Basic net loss per share attributable to common stockholders (in dollars per share)	$ (0.01)	$ 0.03	$ (0.05)	$ (0.02)
Diluted net loss per share attributable to common stockholders (in dollars per share)	$ (0.01)	$ 0.02	$ (0.05)	$ (0.02)
Under Previous Guidance
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product revenue	$ 1,587,748		$ 5,662,884
Support and services revenue	3,052,246		9,140,187
Selling and marketing	1,132,675		3,201,380
Income tax expense (benefit)	(96,858)		(33,868)
Net income (loss)	259,000		916,274
Net income attributable to common stockholders	$ (95,015)		$ (2,280,663)
Basic net loss per share attributable to common stockholders (in dollars per share)	$ 0.00		$ (0.03)
Diluted net loss per share attributable to common stockholders (in dollars per share)	$ 0.00		$ (0.03)
Accounting Standards Update 2014-09 | New Revenue Standard Adjustment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product revenue	$ (579,833)		$ (1,737,380)
Support and services revenue	0		0
Selling and marketing	11,596		8,550
Income tax expense (benefit)	0		0
Net income (loss)	(591,429)		(1,745,930)
Net income attributable to common stockholders	$ (591,429)		$ (1,745,930)
Basic net loss per share attributable to common stockholders (in dollars per share)	$ (0.01)		$ (0.02)
Diluted net loss per share attributable to common stockholders (in dollars per share)	$ (0.01)		$ (0.02)