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 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	0	$ 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, 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 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	0	$ 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)