Recently Adopted and Issued Accounting Guidance - Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Clinical Services	$ 59,540	$ 55,547	$ 116,511	$ 108,455
Pharma Services	8,206	6,717	14,658	11,238
Total Revenue	67,746	62,264	131,169	119,693
Gross Profit	30,530	27,352	57,833	50,301
Total operating expenses	29,736	25,511	54,534	49,038
Income from Operations	794	1,841	3,299	1,263
Interest expense	1,407	1,411	2,892	2,775
Income tax (benefit) expense	(357)	(53)	81	(832)
NET INCOME (LOSS)	$ (380)	483	$ 264	(680)
As Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Clinical Services		59,791		116,482
Pharma Services		6,299		11,285
Total Revenue		66,090		127,767
Gross Profit		31,178		58,374
Total operating expenses		29,864		57,175
Income from Operations		1,314		1,199
Interest expense		1,411		2,775
Income tax (benefit) expense		(54)		(879)
NET INCOME (LOSS)		(43)		(697)
Impact of Adoption | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Clinical Services		(4,244)		(8,027)
Pharma Services		418		(47)
Total Revenue		(3,826)		(8,074)
Gross Profit		(3,826)		(8,073)
Total operating expenses		(4,353)		(8,137)
Income from Operations		527		64
Interest expense		0		0
Income tax (benefit) expense		1		47
NET INCOME (LOSS)		$ 526		$ 17