Fair Value Measurements - Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 3,557	$ 4,173
Contingent consideration resulting from acquisitions		39
Payment of GVi contingent consideration	(1,000)
Ending balance	2,554	3,557
EnShape GmbH [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Payment of contingent consideration		(1,401)
Manatee Works, Inc. [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value adjustment	(1,350)	(325)
Payment of contingent consideration		(525)
Chiaro Technologies LLC [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value adjustment	282	15
GVi Ventures, Inc. [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration resulting from acquisitions		1,299
Fair value adjustment	$ 1,065	$ 282