CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS’ EQUITY/(DEFICIT) - USD ($) $ in Thousands	Total	Common Shares	Additional Paid in Capital	Deficit Accumulated
Balance, beginning of period (in shares) at Dec. 31, 2014		96,609,764
Balance, beginning of period at Dec. 31, 2014	$ (5,159)	$ 11	$ 261,715	$ (266,885)
Increase (Decrease) in Stockholders' Equity
Common stock issued pursuant to a controlled equity “at-the-market” sales agreement, net of issuance costs (in shares)		3,435,998
Common stock issued pursuant to a controlled equity “at-the-market” sales agreement, net of issuance costs	14,268	$ 0	14,268
Common stock issued in connection with exercise of stock options (in shares)		269,720
Common stock issued in connection with exercise of stock options	1,142		1,142
Common stock issued in connection with exercise of warrants (in shares)		189,412
Common stock issued in connection with exercise of warrants	1,012	$ 0	1,012
Notes conversions (in shares)		13,179,712
Notes conversions	40,989	$ 0	40,989
Change in fair value of warrants due to expiration of certain warrants	244		244
Stock based compensation expense	9,724		9,724
Stock issued in exchange for certain intellectual property (in shares)		10,000
Stock issued in exchange for certain intellectual property	67		67
Net loss for the period	(117,500)			(117,500)
Balance, end of period (in shares) at Dec. 31, 2015		113,694,606
Balance, end of period at Dec. 31, 2015	(55,213)	$ 11	329,161	(384,385)
Increase (Decrease) in Stockholders' Equity
Debt conversion expense (in shares)		12,161,671
Debt conversion expense	40,158	$ 1	40,157
Transaction fees on Note conversions	(711)		(711)	0
Common stock issued in connection with exercise of stock options (in shares)		70,185
Common stock issued in connection with exercise of stock options	222		222
Common stock issued in connection with exercise of warrants (in shares)		2,430,656
Common stock issued in connection with exercise of warrants	11,331	$ 1	11,330
Notes conversions (in shares)		44,432,408
Notes conversions	137,941	$ 4	137,937
Common stock issued in registered direct offering, net of issuance costs (in shares)		29,948,334
Common stock issued in registered direct offering, net of issuance costs	89,845	$ 3	89,842
Stock based compensation expense	12,575		12,575
Net loss for the period	$ (198,607)			(198,607)
Balance, end of period (in shares) at Dec. 31, 2016	202,737,860	202,737,860
Balance, end of period at Dec. 31, 2016	$ 37,541	$ 20	620,513	(582,992)
Increase (Decrease) in Stockholders' Equity
Debt conversion expense (in shares)		212,800
Debt conversion expense	1,209	$ 0	1,209
Common stock issued in connection with exercise of stock options (in shares)		99,978
Common stock issued in connection with exercise of stock options	347		347
Notes conversions (in shares)		1,579,099
Notes conversions	4,912	$ 1	4,911
Common stock issued in registered direct offering, net of issuance costs (in shares)		42,030,630
Common stock issued in registered direct offering, net of issuance costs	173,802	$ 4	173,798
Warrants classified as derivative liability	(21,706)		(21,706)
Stock based compensation expense	22,715		22,715
Net loss for the period	$ (224,338)			(224,338)
Balance, end of period (in shares) at Dec. 31, 2017	246,660,367	246,660,367
Balance, end of period at Dec. 31, 2017	$ (5,518)	$ 25	$ 801,787	$ (807,330)