Condensed Consolidated Statement of Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income, net of tax [Member]
Common Stock, Shares, Outstanding, Beginning Balance at Dec. 31, 2017		31,939,175
Stockholders' Equity Attributable to Parent at Dec. 31, 2017	$ (46,979)	$ 36	$ 207,924	$ (13,938)	$ (238,185)	$ (2,816)
Treasury Stock, Shares - Beginning Balance at Dec. 31, 2017				4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues		159,557
Proceeds from Stock Options Exercised	1,201		1,201
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		575,492
Stock Issued During Period, Value, Restricted Stock Award, Gross	(8,968)	$ 1	(8,969)
Stock Issued During Period, Shares, Employee Stock Purchase Plans		37,115
Proceeds from Stock Plans	834		834
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	11,491		11,491
Cumulative effect of adoption of section 606	9,724				9,724
Other Comprehensive Income (Loss), Net of Tax	(262)					(262)
Net Income (Loss) Attributable to Parent	(35,700)				(35,700)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2018				4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2018	(68,659)	$ 37	212,481	$ (13,938)	(264,161)	(3,078)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2018		32,711,339
Common Stock, Shares, Outstanding, Beginning Balance at Mar. 31, 2018		32,588,924
Stockholders' Equity Attributable to Parent at Mar. 31, 2018	(55,139)	$ 37	208,368	$ (13,938)	(247,317)	(2,289)
Treasury Stock, Shares - Beginning Balance at Mar. 31, 2018				4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues		49,649
Proceeds from Stock Options Exercised	326		326
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		72,766
Stock Issued During Period, Value, Restricted Stock Award, Gross	(1,713)		(1,713)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,500		5,500
Other Comprehensive Income (Loss), Net of Tax	(789)					(789)
Net Income (Loss) Attributable to Parent	(16,844)				(16,844)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2018				4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2018	$ (68,659)	$ 37	212,481	$ (13,938)	(264,161)	(3,078)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2018		32,711,339
Common Stock, Shares, Outstanding, Beginning Balance at Dec. 31, 2018	37,155,906	37,155,906
Stockholders' Equity Attributable to Parent at Dec. 31, 2018	$ 54,899	$ 42	364,877	$ (13,938)	(292,708)	(3,374)
Treasury Stock, Shares - Beginning Balance at Dec. 31, 2018	4,417,585			4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from Stock Options Exercised	$ 0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		815,976
Stock Issued During Period, Value, Restricted Stock Award, Gross	$ (18,642)	$ 1	(18,643)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	35,340	35,340
Proceeds from Stock Plans	$ 943		943
Stock Issued During Period, Shares, Conversion of Convertible Securities	2,180,000	2,176,501
Stock Issued During Period, Value, Conversion of Convertible Securities	$ 44,811	$ 2	44,809
Adjustment to additional paid in capital, termination of bond hedge and warrant	64,819		64,819
Adjustment to additional paid in capital, termination of warrant	(45,243)		(45,243)
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	32,883		32,883
Adjustments to Additional Paid in Capital, Other	(16,445)		(16,445)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	11,995		11,995
Other Comprehensive Income (Loss), Net of Tax	(92)					(92)
Net Income (Loss) Attributable to Parent	$ (34,434)				(34,434)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2019	4,417,585			4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2019	$ 95,494	$ 45	439,995	$ (13,938)	(327,142)	(3,466)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2019	40,183,723	40,183,723
Common Stock, Shares, Outstanding, Beginning Balance at Mar. 31, 2019		37,872,661
Stockholders' Equity Attributable to Parent at Mar. 31, 2019	$ 30,470	$ 42	357,635	$ (13,938)	(309,625)	(3,644)
Treasury Stock, Shares - Beginning Balance at Mar. 31, 2019				4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		134,561
Stock Issued During Period, Value, Restricted Stock Award, Gross	$ (4,403)	$ 1	(4,404)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	0
Stock Issued During Period, Shares, Conversion of Convertible Securities		2,176,501
Stock Issued During Period, Value, Conversion of Convertible Securities	$ 44,811	$ 2	44,809
Adjustment to additional paid in capital, termination of bond hedge and warrant	64,819		64,819
Adjustment to additional paid in capital, termination of warrant	(45,243)		(45,243)
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	32,883		32,883
Adjustments to Additional Paid in Capital, Other	(16,445)		(16,445)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,941		5,941
Other Comprehensive Income (Loss), Net of Tax	178					178
Net Income (Loss) Attributable to Parent	$ (17,517)				(17,517)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2019	4,417,585			4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2019	$ 95,494	$ 45	$ 439,995	$ (13,938)	$ (327,142)	$ (3,466)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2019	40,183,723	40,183,723