CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Shares outstanding, beginning balance (in shares) at Dec. 31, 2017		47,236,103
Beginning balance at Dec. 31, 2017	$ 11,865,099	$ 31,459	$ 234,438,057	$ (222,604,417)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)		4,064,310
Issuance of common stock	$ 1,185,452	$ 2,707	1,182,745
Common stock issuance costs (in shares)	615,605
Common stock issuance costs	$ (52,568)	$ 410	(52,978)
Purchase of membership interest (in shares)		1,475,410
Purchase of membership interests	0	$ 983	(983)
Net loss	(2,484,903)			(2,484,903)
Shares outstanding, ending balance (in shares) at Mar. 31, 2018		53,391,428
Ending balance at Mar. 31, 2018	10,513,080	$ 35,559	235,566,841	(225,089,320)
Shares outstanding, beginning balance (in shares) at Dec. 31, 2017		47,236,103
Beginning balance at Dec. 31, 2017	11,865,099	$ 31,459	234,438,057	(222,604,417)
Shares outstanding, ending balance (in shares) at Dec. 31, 2018		75,338,273
Ending balance at Dec. 31, 2018	9,384,902	$ 50,175	241,419,897	(232,085,170)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)		5,452,000
Issuance of common stock	813,561	$ 3,631	809,930
Common stock issuance costs	(85,093)		(85,093)
Net loss	(1,835,065)			(1,835,065)
Shares outstanding, ending balance (in shares) at Mar. 31, 2019		80,790,273
Ending balance at Mar. 31, 2019	$ 8,278,305	$ 53,806	$ 242,144,734	$ (233,920,235)