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	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	3,503,512
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)
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)	$ 0	(968)
Stock-based compensation	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)
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	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	(5,962,673)
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)
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	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)