Segments and Geographic Information - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018 Customer	Jun. 30, 2017 Customer	Jun. 30, 2018 Segment Customer	Jun. 30, 2017 Customer	Dec. 31, 2017 Customer
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments | Segment			2
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Service [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Additional customers accounted for 10% or more of total revenues	0	0	0	0
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Service [Member] | Customer One [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	41.00%	28.00%	37.00%	23.00%
Customer Concentration Risk [Member] | Merck KGaA [Member] | Sales Revenue, Net [Member] | Product Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Customer Concentration Risk [Member] | Merck KGaA [Member] | Accounts Receivable [Member] | Product Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage			100.00%		100.00%
Credit Concentration Risk [Member] | Accounts Receivable [Member] | Service [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of customers			1		1
Credit Concentration Risk [Member] | Accounts Receivable [Member] | Service [Member] | Customer One [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage			47.00%		53.00%