Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring basis - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Assets
Money market	$ 1,390,083	$ 1,390,714
Restricted cash	500,000	894,551
Derivative asset	1,097,223	739,606
Total assets	2,987,306	3,024,871
Liabilities
Contingent consideration		5,000,000
Derivative liability	2,126,536	3,067,572
Total liabilities	2,126,536	8,067,572
Quoted Prices in Active Markets for Identical Items (Level 1)
Assets
Money market	1,390,083	1,390,714
Restricted cash	500,000	894,551
Derivative asset	0	0
Total assets	1,890,083	2,285,265
Liabilities
Contingent consideration		0
Derivative liability	0	0
Total liabilities	0	0
Significant Other Observable Inputs (Level 2)
Assets
Money market	0	0
Restricted cash	0	0
Derivative asset	1,097,223	739,606
Total assets	1,097,223	739,606
Liabilities
Contingent consideration		0
Derivative liability	2,126,536	3,067,572
Total liabilities	2,126,536	3,067,572
Significant Unobservable Inputs (Level 3)
Assets
Money market	0	0
Restricted cash	0	0
Derivative asset	0	0
Total assets	0	0
Liabilities
Contingent consideration		5,000,000
Derivative liability	0	0
Total liabilities	$ 0	$ 5,000,000