CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Total Comprehensive Loss, net	(Accumulated Deficit) Retained Earnings	Noncontrolling Interest in Subsidiary
Beginning Balance (in shares) at Dec. 31, 2014		31,292,000
Beginning Balance at Dec. 31, 2014	$ 130,332	$ 3	$ 247,467	$ (1,118)	$ (116,474)	$ 454
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of share options (in shares)		119,000
Vesting of restricted stock and performance stock awards (in shares)		191,000
Vesting of restricted stock and performance stock awards	(543)		(543)
Equity compensation	2,460		2,460
Foreign currency translation adjustment	(89)			(89)
Acquisition of Mediscan (in shares)		350,000
Acquisition of Mediscan	4,724		4,724
Distribution to noncontrolling shareholder	(494)					(494)
Net income	4,954				4,418	536
Ending Balance (in shares) at Dec. 31, 2015		31,952,000
Ending Balance at Dec. 31, 2015	141,344	$ 3	254,108	(1,207)	(112,056)	496
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of share options (in shares)		103,000
Vesting of restricted stock and performance stock awards (in shares)		284,000
Vesting of restricted stock and performance stock awards	(917)		(917)
Equity compensation	3,379		3,379
Foreign currency translation adjustment	(34)			(34)
Distribution to noncontrolling shareholder	(701)					(701)
Net income	8,731				7,967	764
Ending Balance (in shares) at Dec. 31, 2016		32,339,000
Ending Balance at Dec. 31, 2016	$ 151,802	$ 3	256,570	(1,241)	(104,089)	559
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of share options (in shares)	74,625	41,000
Vesting of restricted stock and performance stock awards (in shares)		282,000
Vesting of restricted stock and performance stock awards	$ (1,774)		(1,774)
Shares issued for Convertible Notes (in shares)		3,176,000
Shares issued for Convertible Notes	45,952	$ 1	45,951
Equity compensation	4,080		4,080
Cumulative-effect adjustment - share-based compensation	0		535		(535)
Foreign currency translation adjustment	75			75
Distribution to noncontrolling shareholder	(1,218)					(1,218)
Net income	38,802				37,513	1,289
Ending Balance (in shares) at Dec. 31, 2017		35,838,000
Ending Balance at Dec. 31, 2017	$ 237,719	$ 4	$ 305,362	$ (1,166)	$ (67,111)	$ 630