3. Operating Lease: Other information related to lease (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 29, 2019	Mar. 30, 2018	Dec. 31, 2018
Operating cashflows
Cash paid related to operating lease obligation	$ 143	$ 137
Remaining lease term (in years) Operating lease	29 days		1 year 29 days

Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (g)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant