Basis of Presentation - Narrative (Details)			3 Months Ended		6 Months Ended
	Feb. 23, 2018 USD ($)	Jan. 01, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Nov. 17, 2017 USD ($)	Dec. 31, 2016 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Working Capital Deficiency			$ (1,600,000)		$ (1,600,000)
Deferred revenue, net			7,245,124		7,245,124		$ 11,760,327
Total Stockholders' Deficit			(11,439,979)		(11,439,979)		(21,224,797)
Net loss			(1,004,104)	$ (639,801)	(497,227)	$ (1,751,998)
Net cash used in operating activities			700,000		700,456	(1,645,279)
Cash and cash equivalents			4,043,668	$ 1,647,695	4,043,668	$ 1,647,695	$ 1,011,472		$ 3,391,528
Cash Period Decrease			3,000,000
Entity number of employees							81
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in deferred revenue			(11,671,762)		(11,671,762)		$ (18,360,690)
Increase in contract assets			2,900,000		2,900,000		$ 0
Finance Commitment Loan | HCP-FVA, LLC
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Aggregate amount of debt	$ 3,000,000							$ 3,000,000
Loan And Security Agreement, Short-Term Loan | HCP-FVA, LLC
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Aggregate amount of debt	500,000							$ 500,000
Loan And Security Agreement, Long-Term Loan | HCP-FVA, LLC
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Aggregate amount of debt	$ 2,500,000.0
Prime rate | Secured Debt | Investor | Finance Commitment Loan
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Variable interest rate	0.75%
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in accumulated deficit		$ 8,900,000
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred revenue, net			(3,596,977)		(3,596,977)
Net loss			$ (1,215,731)		$ (1,101,560)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in deferred revenue		5,400,000
Increase in contract assets		3,100,000
Increase in prepaid expenses and other current assets		$ 400,000