Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income/(loss)	$ 6,088,334	$ (27,212,260)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation	24,115,813	21,436,051
Amortization of deferred drydocking costs	3,893,254	3,058,346
Amortization of debt issuance costs	1,433,971	4,558,145
Amortization of fair value below contract value of time charter acquired	(511,426)	(546,308)
Payment-in-kind interest on debt	0	7,749,872
Net unrealized gain on fair value of derivative instruments	(52,506)	126,651
Stock-based compensation expense	8,020,566	6,998,960
Drydocking expenditures	(6,536,478)	(2,772,678)
Gain on sale of vessels	(340,768)	(2,100,386)
Fees paid on time charter termination	0	(1,500,000)
Changes in operating assets and liabilities:
Accounts receivable	1,103,935	(5,068,678)
Other current and non-current assets	(553,987)	(1,917,446)
Prepaid expenses	742,357	972,635
Inventories	836,648	(1,725,658)
Accounts payable	1,438,208	97,856
Accrued interest	4,161,502	11,578
Other accrued and other non-current liabilities	(4,061,872)	(2,211,819)
Unearned revenue	(1,287,723)	1,527,824
Net cash provided by operating activities	38,489,828	1,482,685
Cash flows from investing activities:
Purchase of vessels and vessel improvements	(20,043,324)	(174,004,286)
Advance paid for purchase of vessel and scrubbers	(8,182,119)	0
Proceeds from redemption of Short-term investment	4,500,000	0
Proceeds from sale of vessels	20,545,202	18,400,000
Purchase of other fixed assets	(148,770)	(183,344)
Net cash used in investing activities	(3,329,011)	(155,787,630)
Cash flows from financing activities:
Proceeds from the common stock private placement, net of issuance costs	0	96,030,003
Cash received from exercise of stock options	4,866	0
Cash used to settle net share equity awards	(2,018,195)	0
Financing costs paid to the lender - Ultraco Debt Facility	0	(918,000)
Other financing costs	(1,428,792)	0
Net cash provided by financing activities	157,879	142,112,003
Net increase/(decrease) in cash and cash equivalents and restricted cash	35,318,696	(12,192,942)
Cash and cash equivalents and restricted cash at beginning of period	56,325,961	76,591,027
Cash and cash equivalents and restricted cash at end of period	91,644,657	64,398,085
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid during the year for interest	13,627,434	8,821,178
Non-cash deferred financing costs included in other liabilities	0	575,000
Ultraco Debt Facility
Cash flows from financing activities:
Proceeds from Ultraco Debt Facility	8,600,000	61,200,000
Term Loan
Cash flows from financing activities:
Repayments of lines of credit	0	(9,200,000)
Revolver Loan | First Lien Facility
Cash flows from financing activities:
Repayments of lines of credit	0	(5,000,000)
Revolver Loan | New First Lien Facility
Cash flows from financing activities:
Repayments of lines of credit	$ (5,000,000)	$ 0