CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Royalties	$ 65,826	$ 112,868
Diagnostic services	28,862	7,618
Clinical research services	350	0
Total revenues	95,038	120,486
Costs and expenses:
Cost of revenues	616,426	309,271
Research and development	4,279,830	3,208,064
Selling and marketing	1,407,985	3,057,552
General and administrative	2,196,639	4,004,247
Restructuring charges	1,719,804	0
Total operating expenses	10,220,684	10,579,134
Loss from operations	(10,125,646)	(10,458,648)
Net interest expense	(429,397)	(337,620)
Gain from change in fair value of derivative financial instruments—warrants	555,506	533,750
Net loss	(9,999,537)	(10,262,518)
Preferred stock dividend	(6,060)	(6,060)
Net loss attributable to common stockholders	$ (10,005,597)	$ (10,268,578)
Net loss per common share - basic (in USD per share)	$ (0.32)	$ (0.35)
Net loss per common share - diluted (in USD per share)	$ (0.32)	$ (0.36)
Weighted average shares outstanding — basic (in shares)	30,961,014	29,755,184
Weighted average shares outstanding — diluted (in shares)	30,961,014	30,108,377