Summary of Significant Accounting Policies - Revision of Previous Financial Statements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2017
Balance Sheet:
Deferred revenue	$ 1,719,003	$ 2,085,080
Total liabilities	16,981,866	18,503,173
Accumulated deficit	(122,119,899)	(123,871,853)
Statement of Stockholders' Deficit:
Cumulative effect of adoption of ASC 606	9,717,099
Total stockholders' deficit at December 31, 2018	(10,765,901)	(14,031,306)	$ (21,224,797)
Previously Reported [Member]
Balance Sheet:
Deferred revenue	2,506,898
Total liabilities	17,769,761
Accumulated deficit	(122,907,794)
Statement of Stockholders' Deficit:
Total stockholders' deficit at December 31, 2018	(11,553,796)
Adjustment [Member]
Balance Sheet:
Deferred revenue	(787,895)
Total liabilities	(787,895)
Accumulated deficit	787,895
Statement of Stockholders' Deficit:
Total stockholders' deficit at December 31, 2018	787,895
Accumulated Deficit
Statement of Stockholders' Deficit:
Cumulative effect of adoption of ASC 606	9,717,099
Total stockholders' deficit at December 31, 2018	(122,119,899)	$ (123,871,853)	$ (130,930,284)
Accumulated Deficit | Previously Reported [Member]
Statement of Stockholders' Deficit:
Cumulative effect of adoption of ASC 606	8,929,204
Total stockholders' deficit at December 31, 2018	(122,907,794)
Accumulated Deficit | Adjustment [Member]
Statement of Stockholders' Deficit:
Cumulative effect of adoption of ASC 606	787,895
Total stockholders' deficit at December 31, 2018	$ 787,895