Basis of Presentation - Impact on the Balance Sheet from Adopting Revenue Recognition Standard (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	$ 1,254,015	$ 1,244,494
Contract assets, net	1,477,619	0
Contract assets, net	1,460,494	0
Deferred revenue, net	7,245,124	11,760,327
Deferred tax liabilities, net	85,559	85,559
Deferred revenue, net	4,426,638	6,600,363
Accumulated deficit	(122,496,878)	$ (130,930,284)
Under Previous Guidance
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	948,272
Contract assets, net	0
Contract assets, net	0
Deferred revenue, net	10,842,101
Deferred tax liabilities, net	85,559
Deferred revenue, net	5,250,834
Accumulated deficit	(130,161,907)
Accounting Standards Update 2014-09 | New Revenue Standard Adjustment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	305,743
Contract assets, net	1,477,619
Contract assets, net	1,460,494
Deferred revenue, net	(3,596,977)
Deferred tax liabilities, net	0
Deferred revenue, net	(824,196)
Accumulated deficit	$ 7,665,029