Fair Values of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($) $ in Thousands	Mar. 29, 2019	Dec. 31, 2018
Assets
Cash equivalents	$ 3,252	$ 4,288
Assets, fair value	3,548	4,303
Liabilities
Liabilities, fair value	3,382	3,558
Prepaid Expenses and Other Current Assets
Assets
Foreign currency forward contracts	296	15
Accrued Expenses and Other Current Liabilities
Liabilities
Contingent consideration - Current	1,248
Foreign currency forward contracts	6	182
Other Liabilities
Liabilities
Contingent consideration - Long-term	2,128	3,376
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash equivalents	3,252	4,288
Assets, fair value	3,252	4,288
Significant Other Observable Inputs (Level 2)
Assets
Assets, fair value	296	15
Liabilities
Liabilities, fair value	6	182
Significant Other Observable Inputs (Level 2) | Prepaid Expenses and Other Current Assets
Assets
Foreign currency forward contracts	296	15
Significant Other Observable Inputs (Level 2) | Accrued Expenses and Other Current Liabilities
Liabilities
Foreign currency forward contracts	6	182
Significant Other Unobservable Inputs (Level 3)
Liabilities
Liabilities, fair value	3,376	3,376
Significant Other Unobservable Inputs (Level 3) | Accrued Expenses and Other Current Liabilities
Liabilities
Contingent consideration - Current	1,248
Significant Other Unobservable Inputs (Level 3) | Other Liabilities
Liabilities
Contingent consideration - Long-term	$ 2,128	$ 3,376