Segment, Geographic, Product and Significant Customer Information - Long-lived Tangible Assets (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Long-lived tangible assets:
Total long-lived tangible assets	$ 43,135	$ 44,810
United States [Member]
Long-lived tangible assets:
Total long-lived tangible assets	42,013	43,427
International [Member]
Long-lived tangible assets:
Total long-lived tangible assets	$ 1,122	$ 1,383

Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e9038-108599

Name:	us-gaap_NoncurrentAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant