Condensed Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2017		70,394,307
Beginning balance at Dec. 31, 2017	$ 461,165,033	$ 703,944	$ 887,625,902	$ (427,164,813)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	52,745			52,745
Issuance of shares due to vesting of restricted shares (in shares)		120,711
Issuance of shares due to vesting of restricted shares		$ 1,207	(1,207)
Cash used to settle net share equity awards	(254,146)		(254,146)
Stock-based compensation expense	3,510,911		3,510,911
Ending balance (in shares) at Mar. 31, 2018		70,515,018
Ending balance at Mar. 31, 2018	463,687,433	$ 705,151	890,881,460	(427,899,178)
Beginning balance (in shares) at Dec. 31, 2017		70,394,307
Beginning balance at Dec. 31, 2017	461,165,033	$ 703,944	887,625,902	(427,164,813)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	6,088,334
Ending balance (in shares) at Sep. 30, 2018		70,924,609
Ending balance at Sep. 30, 2018	472,473,494	$ 709,247	893,627,836	(421,863,589)
Beginning balance (in shares) at Mar. 31, 2018		70,515,018
Beginning balance at Mar. 31, 2018	463,687,433	$ 705,151	890,881,460	(427,899,178)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	3,450,767			3,450,767
Issuance of shares due to vesting of restricted shares (in shares)		1,448
Issuance of shares due to vesting of restricted shares	4,865	$ 14	4,851
Cash used to settle net share equity awards	(968)		(968)
Stock-based compensation expense	2,409,599		2,409,599
Ending balance (in shares) at Jun. 30, 2018		70,516,466
Ending balance at Jun. 30, 2018	469,551,696	$ 705,165	893,294,942	(424,448,411)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	2,584,822			2,584,822
Issuance of shares due to vesting of restricted shares (in shares)		408,143
Issuance of shares due to vesting of restricted shares	1	$ 4,082	(4,081)
Cash used to settle net share equity awards	(1,763,081)		(1,763,081)
Stock-based compensation expense	2,100,056		2,100,056
Ending balance (in shares) at Sep. 30, 2018		70,924,609
Ending balance at Sep. 30, 2018	472,473,494	$ 709,247	893,627,836	(421,863,589)
Beginning balance (in shares) at Dec. 31, 2018		71,055,400
Beginning balance at Dec. 31, 2018	479,605,849	$ 710,555	894,272,533	(415,377,239)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	29,483			29,483
Issuance of shares due to vesting of restricted shares (in shares)		293,011
Issuance of shares due to vesting of restricted shares		$ 2,929	(2,929)
Cash used to settle net share equity awards	(877,161)		(877,161)
Stock-based compensation expense	1,445,469		1,445,469
Ending balance (in shares) at Mar. 31, 2019		71,348,411
Ending balance at Mar. 31, 2019	480,203,640	$ 713,484	894,837,912	(415,347,756)
Beginning balance (in shares) at Dec. 31, 2018		71,055,400
Beginning balance at Dec. 31, 2018	479,605,849	$ 710,555	894,272,533	(415,377,239)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	(10,525,662)
Ending balance (in shares) at Sep. 30, 2019		71,474,676
Ending balance at Sep. 30, 2019	491,776,892	$ 714,747	916,965,046	(425,902,901)
Beginning balance (in shares) at Mar. 31, 2019		71,348,411
Beginning balance at Mar. 31, 2019	480,203,640	$ 713,484	894,837,912	(415,347,756)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	(5,992,156)			(5,992,156)
Issuance of shares due to vesting of restricted shares (in shares)		113
Issuance of shares due to vesting of restricted shares		$ 1	(1)
Cash used to settle net share equity awards	(536)		(536)
Stock-based compensation expense	1,227,210		1,227,210
Ending balance (in shares) at Jun. 30, 2019		71,348,524
Ending balance at Jun. 30, 2019	475,438,158	$ 713,485	896,064,585	(421,339,912)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/income	(4,562,989)			(4,562,989)
Issuance of shares due to vesting of restricted shares (in shares)		126,152
Issuance of shares due to vesting of restricted shares		$ 1,262	(1,262)
Proceeds received as per the Share Lending Agreement	35,829		35,829
Equity component of Convertible Bond Debt, net of equity issuance costs	20,181,907		20,181,907
Cash used to settle net share equity awards	(471,236)		(471,236)
Stock-based compensation expense	1,155,223		1,155,223
Ending balance (in shares) at Sep. 30, 2019		71,474,676
Ending balance at Sep. 30, 2019	$ 491,776,892	$ 714,747	$ 916,965,046	$ (425,902,901)