Recently Adopted and Issued Accounting Guidance - Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 69,096	$ 59,137	$ 200,266	$ 178,830
Gross Profit	32,321	24,895	90,155	75,196
Total operating expenses	28,401	26,959	82,936	75,997
Income from Operations	3,920	(2,064)	7,219	(801)
Interest expense	1,873	1,398	4,766	4,173
Income tax (benefit) expense	54	802	135	(30)
NET INCOME (LOSS)	2,023	(4,264)	2,287	(4,944)
As Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues		63,052		190,818
Gross Profit		28,810		87,184
Total operating expenses		32,172		89,347
Income from Operations		(3,362)		(2,163)
Interest expense		1,398		4,173
Income tax (benefit) expense		340		(539)
NET INCOME (LOSS)		(5,100)		(5,797)
Impact of Adoption | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues		(3,915)		(11,988)
Gross Profit		(3,915)		(11,988)
Total operating expenses		(5,213)		(13,350)
Income from Operations		1,298		1,362
Interest expense		0		0
Income tax (benefit) expense		462		509
NET INCOME (LOSS)		836		853
Clinical Services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	59,449	51,187	175,960	159,642
Gross Profit	27,940	21,037	81,374	67,788
Clinical Services | As Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues		56,186		172,667
Clinical Services | Impact of Adoption | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues		(4,999)		(13,025)
Pharma Services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	9,647	7,950	24,306	19,188
Gross Profit	$ 4,381	3,858	$ 8,781	7,408
Pharma Services | As Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues		6,866		18,151
Pharma Services | Impact of Adoption | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues		$ 1,084		$ 1,037