Basis of Presentation - Impact on the Balance Sheet from Adopting Revenue Recognition Standard (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	$ 1,415,950	$ 1,244,494
Contract assets, net	1,624,533	0
Contract assets, net	1,786,369	0
Deferred revenue, net	7,391,371	11,760,327
Deferred tax liabilities, net	85,559	85,559
Deferred revenue, net	5,748,448	6,600,363
Accumulated deficit	(121,492,776)	$ (130,930,284)
Under Previous Guidance
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	1,036,979
Contract assets, net	0
Contract assets, net	0
Deferred revenue, net	12,407,725
Deferred tax liabilities, net	85,559
Deferred revenue, net	6,106,637
Accumulated deficit	(130,657,192)
Accounting Standards Update 2014-09 | New Revenue Standard Adjustment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	378,971
Contract assets, net	1,624,533
Contract assets, net	1,786,369
Deferred revenue, net	(5,016,354)
Deferred tax liabilities, net	0
Deferred revenue, net	(358,189)
Accumulated deficit	$ 9,164,416