CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Royalties	$ 49,055	$ 65,826
Diagnostic services	40,002	28,862
Clinical research	11,079	350
Total revenues	100,136	95,038
Costs and expenses:
Cost of revenues	366,344	616,426
Research and development	1,883,838	4,279,830
Selling, general and administrative	2,504,977	3,604,624
Restructuring charges	0	1,719,804
Total operating expenses	4,755,159	10,220,684
Loss from operations	(4,655,023)	(10,125,646)
Net interest expense	(2,465)	(429,397)
(Loss) gain from change in fair value of derivative financial instruments—warrants	(129,689)	555,506
Other income	1,000	0
Net loss	(4,786,177)	(9,999,537)
Preferred stock dividend	(6,060)	(6,060)
Net loss attributable to common stockholders	$ (4,792,237)	$ (10,005,597)
Net loss per common share - basic (in USD per share)	$ (0.09)	$ (0.32)
Net loss per common share - diluted (in USD per share)	$ (0.09)	$ (0.32)
Weighted-average shares outstanding — basic (in shares)	55,364,438	30,961,014
Weighted-average shares outstanding — diluted (in shares)	55,364,438	30,961,014