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Operating Segments and Enterprise-Wide Information - Revenue by Segment, Recognition Type, and Geographic Area (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 25, 2021 | Sep. 26, 2020 | Sep. 25, 2021 | Sep. 26, 2020
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 189,964 | $ 177,996 | $ 564,676 | $ 496,573
Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 154,850 | 150,773 | 467,389 | 419,272
Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 35,114 | 27,223 | 97,287 | 77,301
Taiwan |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 41,574 | 36,935 | 139,038 | 101,886
Taiwan | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 34,100 | 33,351 | 125,571 | 93,596
Taiwan | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 7,474 | 3,584 | 13,467 | 8,290
South Korea |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 28,972 | 29,571 | 84,234 | 58,772
South Korea | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 27,895 | 28,337 | 81,322 | 56,278
South Korea | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 1,077 | 1,234 | 2,912 | 2,494
United States |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 25,468 | 36,328 | 87,604 | 96,365
United States | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 18,530 | 31,596 | 64,012 | 79,575
United States | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 6,938 | 4,732 | 23,592 | 16,790
China |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 51,047 | 28,546 | 125,499 | 120,946
China | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 46,011 | 24,851 | 107,838 | 107,756
China | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 5,036 | 3,695 | 17,661 | 13,190
Asia-Pacific |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 19,881 | 8,954 | 63,127 | 23,317
Asia-Pacific | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 18,566 | 5,505 | 59,013 | 14,307
Asia-Pacific | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 1,315 | 3,449 | 4,114 | 9,010
Europe |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 10,486 | 16,979 | 32,495 | 52,154
Europe | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 3,595 | 11,679 | 12,894 | 36,656
Europe | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 6,891 | 5,300 | 19,601 | 15,498
Japan |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 10,728 | 17,145 | 27,753 | 35,574
Japan | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 5,767 | 12,288 | 14,493 | 24,502
Japan | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 4,961 | 4,857 | 13,260 | 11,072
Rest of the world |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 1,808 | 3,538 | 4,926 | 7,559
Rest of the world | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 386 | 3,166 | 2,246 | 6,602
Rest of the world | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 1,422 | 372 | 2,680 | 957
Products transferred at a point in time |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 187,781 | 176,239 | 554,941 | 490,922
Products transferred at a point in time | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 154,217 | 150,252 | 465,822 | 417,529
Products transferred at a point in time | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 33,564 | 25,987 | 89,119 | 73,393
Products and services transferred over time |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 2,183 | 1,757 | 9,735 | 5,651
Products and services transferred over time | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 633 | 521 | 1,567 | 1,743
Products and services transferred over time | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 1,550 | 1,236 | 8,168 | 3,908
Foundry & Logic |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 104,640 | 108,411 | 321,776 | 323,503
Foundry & Logic | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 104,640 | 108,411 | 321,776 | 323,503
Foundry & Logic | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
DRAM |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 39,816 | 31,379 | 115,802 | 75,127
DRAM | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 39,816 | 31,379 | 115,802 | 75,127
DRAM | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Flash |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 10,394 | 10,983 | 29,811 | 20,642
Flash | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 10,394 | 10,983 | 29,811 | 20,642
Flash | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 35,114 | 27,223 | 97,287 | 77,301
Systems | Probe Cards |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Systems | Systems |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 35,114 | $ 27,223 | $ 97,287 | $ 77,301

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