Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Conversion of Series F Preferred Stock into Common Stock [Member]	Conversion Of Series C-1 And D-1 Preferred Stock Into Common Stock [Member]	Preferred Stock [Member] Series C-1 Convertible Preferred Stock [Member]	Preferred Stock [Member] Series C-1 Convertible Preferred Stock [Member] Conversion Of Series C-1 And D-1 Preferred Stock Into Common Stock [Member]	Preferred Stock [Member] Series F Convertible Preferred Stock [Member]	Preferred Stock [Member] Series F Convertible Preferred Stock [Member] Conversion of Series F Preferred Stock into Common Stock [Member]	Common Stock [Member]	Common Stock [Member] Conversion of Series F Preferred Stock into Common Stock [Member]	Common Stock [Member] Conversion Of Series C-1 And D-1 Preferred Stock Into Common Stock [Member]	Common Stock [Member] Series C-1 Convertible Preferred Stock [Member]	Common Stock [Member] Series F Convertible Preferred Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Conversion of Series F Preferred Stock into Common Stock [Member]	Additional Paid-in Capital [Member] Conversion Of Series C-1 And D-1 Preferred Stock Into Common Stock [Member]	Retained Earnings [Member]
Beginning Balance (in shares) at Dec. 31, 2014				4,000		3,000		15,226,000
Beginning Balance at Dec. 31, 2014	$ 48,456			$ 3,917		$ 2,798		$ 2					$ 528,353			$ (486,614)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued during period (in shares)								2,933,000			19,134	17,360
Stock issued during period, value	104,596												104,596
Conversion of Convertible Preferred Stock into common stock		$ 0	$ 0		$ (11)		$ (61)							$ 61	$ 11
Conversion of Convertible Preferred Stock into common stock (in shares)									17,000	19,000
Share-based compensation expense	11,551												11,551
Third party share-based compensation expense	$ 1,521												1,521
Exercise of stock options for common stock (in shares)	51,814							45,000
Exercise of stock options for common stock	$ 315												315
Issuance of restricted stock awards (in shares)								4,000
Issuance of restricted stock awards	0
Net loss	(41,912)															(41,912)
Ending Balance (in shares) at Dec. 31, 2015				4,000		3,000		18,244,000
Ending Balance at Dec. 31, 2015	124,527			$ 3,906		$ 2,737		$ 2					646,408			(528,526)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	14,349												14,349
Third party share-based compensation expense	$ 197												197
Exercise of stock options for common stock (in shares)	17,548							17,000
Exercise of stock options for common stock	$ 149												149
Net loss	(78,185)															(78,185)
Ending Balance (in shares) at Dec. 31, 2016				4,000		3,000		18,261,000
Ending Balance at Dec. 31, 2016	61,037			$ 3,906		$ 2,737		$ 2					661,103			(606,711)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued during period (in shares)								3,731,000
Stock issued during period, value	117,480												117,480
Share-based compensation expense	20,776												20,776
Third party share-based compensation expense	$ 1,019												1,019
Exercise of stock options for common stock (in shares)	174,628							175,000
Exercise of stock options for common stock	$ 2,693												2,693
Net loss	(114,803)															(114,803)
Ending Balance (in shares) at Dec. 31, 2017				4,000		3,000		22,167,000
Ending Balance at Dec. 31, 2017	$ 88,202			$ 3,906		$ 2,737		$ 2					$ 803,071			$ (721,514)