2. Revenue: Schedule of geographical revenues (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 29, 2018	Jun. 29, 2018
Application total
Product Application	$ 8,872	$ 16,453
Transferred at Point in Time
Product Application	1,078	1,559
Transferred over Time
Product Application	7,794	14,894
Audio-Visual Systems
Product Application	4,410	8,407
Domes
Product Application	2,876	5,578
Show Content
Product Application	844	1,170
Maintenance and Service
Product Application	742	1,298
North America
Product Application	6,393	10,006
Europe
Product Application	1,499	1,843
Asia
Product Application	969	4,272
Other
Product Application	11	332
Planetarium Theaters | Application total
Product Application	7,103	13,346
Planetarium Theaters | Transferred at Point in Time
Product Application	1,078	1,559
Planetarium Theaters | Transferred over Time
Product Application	6,025	11,787
Planetarium Theaters | Audio-Visual Systems
Product Application	4,009	7,995
Planetarium Theaters | Domes
Product Application	1,508	2,883
Planetarium Theaters | Show Content
Product Application	844	1,170
Planetarium Theaters | Maintenance and Service
Product Application	742	1,298
Planetarium Theaters | North America
Product Application	5,771	8,904
Planetarium Theaters | Europe
Product Application	1,098	1,431
Planetarium Theaters | Asia
Product Application	223	2,679
Planetarium Theaters | Other
Product Application	11	332
Other Visitor Attractions | Application total
Product Application	1,500	2,478
Other Visitor Attractions | Transferred at Point in Time
Product Application	0	0
Other Visitor Attractions | Transferred over Time
Product Application	1,500	2,478
Other Visitor Attractions | Audio-Visual Systems
Product Application	401	412
Other Visitor Attractions | Domes
Product Application	1,099	2,066
Other Visitor Attractions | Show Content
Product Application	0	0
Other Visitor Attractions | Maintenance and Service
Product Application	0	0
Other Visitor Attractions | North America
Product Application	353	473
Other Visitor Attractions | Europe
Product Application	401	412
Other Visitor Attractions | Asia
Product Application	746	1,593
Other Visitor Attractions | Other
Product Application	0	0
Architectural Treatments | Application total
Product Application	269	629
Architectural Treatments | Transferred at Point in Time
Product Application	0	0
Architectural Treatments | Transferred over Time
Product Application	269	629
Architectural Treatments | Audio-Visual Systems
Product Application	0	0
Architectural Treatments | Domes
Product Application	269	629
Architectural Treatments | Show Content
Product Application	0	0
Architectural Treatments | Maintenance and Service
Product Application	0	0
Architectural Treatments | North America
Product Application	269	629
Architectural Treatments | Europe
Product Application	0	0
Architectural Treatments | Asia
Product Application	0	0
Architectural Treatments | Other
Product Application	$ 0	$ 0