CONSOLIDATED STATEMENTS OF SHAREHOLDERS' (DEFICIT) EQUITY - USD ($) shares in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
Balance at Dec. 31, 2016	$ 873,000	$ 778,847,000	$ (932,570,000)	$ (152,850,000)
Balance (in shares) at Dec. 31, 2016	87,301
Increase (Decrease) in Shareholders' (Deficit) Equity
Net loss			(96,012,000)	(96,012,000)
Stock options exercised	$ 1,000	649,000		650,000
Stock options exercised (in shares)	191
Issuance of common stock	$ 167,000	101,496,000		101,663,000
Issuance of common stock (in shares)	16,675
Restricted stock award - net of forfeitures	$ 21,000	(21,000)
Restricted stock award - net of forfeitures (in shares)	2,146
Conversion of debt	$ 262,000	117,067,000		117,329,000
Conversion of debt (in shares)	26,160
Stock option and restricted stock compensation expense		11,119,000		11,119,000
Directors' deferred share units converted	$ 1,000	(1,000)
Directors' deferred share units converted (in shares)	53
Directors' deferred share unit compensation		206,000		206,000
Balance at Dec. 31, 2017	$ 1,325,000	1,009,362,000	(1,028,582,000)	(17,895,000)
Balance (in shares) at Dec. 31, 2017	132,526
Increase (Decrease) in Shareholders' (Deficit) Equity
Net loss			(168,843,000)	(168,843,000)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	$ 9,000	4,292,000		4,301,000
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan (in shares)	946
Issuance of common stock	$ 158,000	162,354,000		162,512,000
Issuance of common stock (in shares)	15,755
Stock option and restricted stock compensation expense		16,445,000		16,445,000
Directors' deferred share units converted	$ 2,000	(1,000)		1,000
Directors' deferred share units converted (in shares)	173
Directors' deferred share unit compensation		361,000		361,000
Balance at Dec. 31, 2018	$ 1,494,000	1,192,813,000	(1,183,335,000)	$ 10,972,000
Balance (in shares) at Dec. 31, 2018	149,400			149,400
Increase (Decrease) in Shareholders' (Deficit) Equity
Transition adjustment for ASC 606			14,090,000	$ 14,090,000
Net loss			(104,133,000)	(104,133,000)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	$ 11,000	2,862,000		2,873,000
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan (in shares)	1,150
Restricted stock award - net of forfeitures	$ (4,000)	4,000
Restricted stock award - net of forfeitures (in shares)	(414)
Stock option and restricted stock compensation expense		13,830,000		13,830,000
Directors' deferred share unit compensation		337,000		337,000
Balance at Dec. 31, 2019	$ 1,501,000	$ 1,209,846,000	$ (1,287,468,000)	$ (76,121,000)
Balance (in shares) at Dec. 31, 2019	150,136			150,136