CONSOLIDATED STATEMENTS OF SHAREHOLDERS' (DEFICIT) EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
Balance at Dec. 31, 2016	$ 873	$ 778,847	$ (932,570)	$ (152,850)
Balance (in shares) at Dec. 31, 2016	87,301
Increase (Decrease) in Shareholders' (Deficit) Equity
Net loss			(96,012)	(96,012)
Stock options exercised	$ 1	649		650
Stock options exercised (in shares)	191
Restricted stock award - net of forfeitures	$ 21	(21)
Restricted stock award - net of forfeitures (in shares)	2,146
Stock option and restricted stock compensation expense		11,119		11,119
Directors' deferred share units converted	$ 1	(1)
Directors' deferred share units converted (in shares)	53
Issuance of common stock	$ 167	101,496		101,663
Issuance of common stock (in shares)	16,675
Conversion of debt	$ 262	117,067		117,329
Conversion of debt (in shares)	26,160
Directors' deferred share unit compensation		206		206
Balance at Dec. 31, 2017	$ 1,325	1,009,362	(1,028,582)	$ (17,895)
Balance (in shares) at Dec. 31, 2017	132,526			132,526
Increase (Decrease) in Shareholders' (Deficit) Equity
Net loss			(127,044)	$ (127,044)
Stock options exercised	$ 6	2,937		2,943
Stock options exercised (in shares)	595
Stock option and restricted stock compensation expense		12,024		12,024
Directors' deferred share units converted	$ 1	(1)
Directors' deferred share units converted (in shares)	173
Issuance of common stock	$ 158	162,354		162,512
Issuance of common stock (in shares)	15,755
Directors' deferred share unit compensation		258		258
Balance at Sep. 30, 2018	$ 1,490	$ 1,186,934	(1,141,536)	$ 46,888
Balance (in shares) at Sep. 30, 2018	149,049			149,049
Increase (Decrease) in Shareholders' (Deficit) Equity
Transition adjustment for ASC 606			$ 14,090	$ 14,090