Significant Accounting Policies - Narrative (Details)	3 Months Ended	12 Months Ended
	Jun. 30, 2017 USD ($)	Dec. 31, 2018 USD ($) t	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2019 USD ($)	Jan. 01, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Restricted cash			$ 100,000
Restricted cash and cash equivalents		$ 74,917
Write off of allowance for doubtful accounts		1,400,000	3,400,000
Certificates of deposit			4,500,000
Asset impairment charges		$ 0	0	$ 129,000,000
Amortization period for vessels over fifteen years old		30 months
Age of vessels		15 years
Amortization period for vessels less than fifteen years old		60 months
Deferred financing costs - Super Senior Facility		$ 285,342	190,000
Vessel useful lives		3 years
Accumulated deficit		$ 415,377,239	427,164,813			$ 427,951,923
Tax expense	$ (600,000)			600,000
Other current assets		2,246,740	785,027			1,581,535
Unearned charter hire revenue		6,926,839	5,678,673			6,336,308
Restricted cash		10,953,885	74,917
Cash paid towards payment-in-kind interest on Second Lien Facility		0	17,426,244	$ 0
Calculated under Revenue Guidance in Effect before Topic 606
Property, Plant and Equipment [Line Items]
Accumulated deficit			427,164,813
Other current assets		1,478,450	785,027
Unearned charter hire revenue		6,528,275	5,678,673
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Property, Plant and Equipment [Line Items]
Accumulated deficit			787,110			800,000
Other current assets		768,290	796,508			800,000
Unearned charter hire revenue		398,564	657,635			1,600,000
Super Senior Revolver Facility | Revolving Credit Facility
Property, Plant and Equipment [Line Items]
Proceeds from lines of credit		0
Vessel Thrush
Property, Plant and Equipment [Line Items]
Restricted cash		$ 11,000,000
Vessels
Property, Plant and Equipment [Line Items]
Scrap value of vessels | t		300
Bunker Expenses | Calculated under Revenue Guidance in Effect before Topic 606
Property, Plant and Equipment [Line Items]
Other current assets						600,000
Charter Hire Expenses | Calculated under Revenue Guidance in Effect before Topic 606
Property, Plant and Equipment [Line Items]
Other current assets						200,000
Voyage In Progress | Calculated under Revenue Guidance in Effect before Topic 606
Property, Plant and Equipment [Line Items]
Unearned charter hire revenue						$ 700,000
Subsequent Event | Accounting Standards Update 2016-02 | Minimum | Scenario, Forecast
Property, Plant and Equipment [Line Items]
Right of use asset					$ 27,000,000
Lease liability					27,000,000
Subsequent Event | Accounting Standards Update 2016-02 | Maximum | Scenario, Forecast
Property, Plant and Equipment [Line Items]
Right of use asset					35,000,000
Lease liability					$ 35,000,000
Letter of Credit
Property, Plant and Equipment [Line Items]
Restricted cash and cash equivalents		$ 74,917	$ 74,917