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Related Party Transactions - Narrative (Detail) |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 14, 2020 USD ($) | Oct. 02, 2020 USD ($) shares | Mar. 28, 2020 USD ($) | Mar. 31, 2019 USD ($) | Dec. 31, 2017 USD ($) shares | Sep. 30, 2017 USD ($) shares | Dec. 25, 2020 USD ($) | Dec. 27, 2019 USD ($) | Dec. 25, 2020 USD ($) | Dec. 27, 2019 USD ($) | Mar. 27, 2020 USD ($) Note LettersOfCredit | Mar. 29, 2019 USD ($) | Dec. 25, 2019 USD ($) | Jun. 30, 2018 USD ($) | May 31, 2018 USD ($)
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  | $ 164,449,000 | $ 159,802,000 | $ 416,099,000 | $ 475,485,000 | $ 650,089,000 | $ 724,311,000 |  |  |
Trade accounts receivable from related party |  |  |  |  |  |  | 19,778,000 |  | 19,778,000 |  | 30,293,000 | 6,879,000 |  |  |
Amounts due to related party |  |  |  |  |  |  | 2,078,000 |  | 2,078,000 |  | 4,494,000 | 4,941,000 |  |  |
Promissory notes outstanding |  |  |  |  |  |  |  |  |  |  |  | 30,000,000 |  |  |
Related party notes payable, less current portion |  |  |  |  |  |  |  |  |  |  | 17,700,000 | 14,700,000 |  |  |
Current portion of related party debt |  |  |  |  |  |  |  |  |  |  | $ 25,000,000 | 13,000,000 |  |  |
Long-term maturity dates |  |  |  |  |  |  |  |  |  |  | Mar. 14, 2025 |  |  |  |
Accounts payable |  |  |  |  |  |  | 20,262,000 |  | 20,262,000 |  | $ 20,762,000 | 24,189,000 |  |  |
Trade accounts receivable, net |  |  |  |  |  |  | 67,334,000 |  | 67,334,000 |  | 59,457,000 | 76,444,000 |  |  |
Paid fees |  |  |  |  |  |  | 300,000 |  | 900,000 |  |  |  |  |  |
Received fees |  |  |  |  |  |  | 300,000 | 300,000 | 900,000 | 900,000 |  |  |  |  |
Cost of goods sold |  |  |  |  |  |  | 90,024,000 | 98,277,000 | 224,203,000 | 285,967,000 | 388,813,000 | 404,491,000 |  |  |
Common Class L |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repurchase of stock | shares |  | 1,997 |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price |  | $ 408,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Consolidation, Eliminations [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Accounts payable |  |  | $ 1,198,000 |  |  |  |  |  |  |  |  |  |  |  |
Trade accounts receivable, net |  |  | $ 3,368,000 |  |  |  | 3,368,000 |  | 3,368,000 |  |  |  | $ 2,528,000 |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  | 2.70% |  |  |  |  |  |  |  |  |  |  |  |
Interest paid | $ 762,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related party debt |  |  | $ 66,377,000 |  |  |  |  |  |  |  |  |  |  |  |
Noncash or part noncash divestiture, amount of consideration received |  |  |  |  |  |  |  |  |  |  | $ 42,700,000 |  |  |  |
Forgiveness of the fair value |  |  | 15,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Repayments of related party notes receivable | $ 51,377,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Sanken |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related party debt |  |  | $ 42,700,000 |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage by majority shareholder |  |  | 70.00% |  |  |  |  |  |  |  |  |  |  |  |
Forgiveness of the fair value |  |  | $ 15,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Sanken | Disposal Group, Disposed of by Sale, Not Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage by majority shareholder |  |  |  |  |  |  |  |  |  |  | 70.00% |  |  |  |
Sanken |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Trade accounts receivable from related party |  |  |  |  |  |  | 17,250,000 |  | 17,250,000 |  | $ 30,293,000 | 6,879,000 |  |  |
Other accounts receivable from related party |  |  |  |  |  |  | 374,000 |  | 374,000 |  | 558,000 | 473,000 |  |  |
Purchases from related party |  |  |  |  |  |  |  | 7,356,000 |  | 23,835,000 | 31,917,000 | 32,732,000 |  |  |
Amounts due to related party |  |  |  |  |  |  |  |  |  |  | 4,494,000 | 4,941,000 |  |  |
Reimbursement of development costs |  |  |  |  |  |  | 0 | 360,000 | 0 | 1,080,000 | 1,440,000 | 1,440,000 |  |  |
Promissory notes outstanding |  |  |  | $ 30,000,000 |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  | 2.52% |  |  |  |  |  |  |  |  |  |  |
Interest income |  |  |  |  |  |  |  |  |  | 55,000 | $ 55,000 | 0 |  |  |
Number of notes payable | Note |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |
Related party notes payable, less current portion |  |  |  |  |  |  |  |  |  |  | $ 17,700,000 | 14,700,000 |  |  |
Number of line-of-credit agreements | LettersOfCredit |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |
Current portion of related party debt |  |  |  |  |  |  |  |  |  |  | $ 25,000,000 | 3,000,000 |  |  |
Basis spread on variable rate |  |  |  |  |  |  |  |  |  |  | 1.00% |  |  |  |
Interest expense |  |  |  |  |  |  |  | 334,000 |  | 1,129,000 | $ 1,444,000 | 1,666,000 |  |  |
Interest paid |  |  |  |  |  |  |  | 81,000 |  | 835,000 | 1,538,000 | 1,664,000 |  |  |
Related party debt |  |  |  |  |  |  |  |  |  |  | 17,700,000 | 17,700,000 |  |  |
Aggregate sublease payments |  |  |  |  |  |  |  |  |  |  | 200,000 | 200,000 |  |  |
Sanken | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related party notes payable, less current portion |  |  |  |  |  |  |  |  |  |  |  | 15,000,000 |  |  |
Current portion of related party debt |  |  |  |  |  |  |  |  |  |  | 25,000,000 | 10,000,000 |  |  |
Related party debt |  |  |  |  |  |  |  |  |  |  |  | 25,000,000 |  |  |
Director |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Monthly fee payable |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 19,000 | $ 30,000
Signing fee |  |  |  |  | $ 54,000 | $ 54,000 |  |  |  |  |  |  |  |  |
Severance payment if terminated |  |  |  |  | $ 180,000 | $ 180,000 |  |  |  |  |  |  |  |  |
Accelerated vesting, acceleration period |  |  |  |  | 6 months | 6 months |  |  |  |  |  |  |  |  |
Related party transaction amounts |  |  |  |  |  |  |  |  | 262,000 | 270,000 | 494,000 | 360,000 |  |  |
Director | Common Class L |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shares granted (in shares) | shares |  |  |  |  | 12,000 | 12,000,000 |  |  |  |  |  |  |  |  |
Director | Previously Reported |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Monthly fee payable |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 18,750 |
Directors and executive officers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related party debt |  |  |  |  |  |  |  |  |  |  | 506,000 | 506,000 |  |  |
Equity Method Investee [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchases from related party |  |  |  |  |  |  | 11,558,000 |  | 33,448,000 |  |  |  |  |  |
Amounts due to related party |  |  |  |  |  |  | 2,078,000 |  | 2,078,000 |  |  |  |  |  |
Equity Method Investee [Member] | Price Support Payment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchases from related party |  |  |  |  |  |  | 1,500,000 |  | 5,000,000 |  |  |  |  |  |
Equity Method Investee [Member] | Consolidation, Eliminations [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cost of goods sold |  |  |  |  |  |  | 1,157,000 |  | 1,198,000 |  |  |  |  |  |
Discrete Technology Development Agreements [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Paid fees |  |  |  |  |  |  | 0 | 0 | 0 | 0 |  |  |  |  |
Related Party Revenue |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  | 26,439,000 | 16,535,000 | 72,570,000 | 49,327,000 | 184,557,000 | 191,372,000 |  |  |
Related Party Revenue | Sanken |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  | $ 26,439,000 | 16,535,000 | $ 72,570,000 | 49,327,000 | 184,557,000 | 191,372,000 |  |  |
Distribution of Sanken products |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  | 7,666,000 |  | 26,688,000 | 35,421,000 |  |  |  |
Distribution of Sanken products | Sanken |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  | $ 7,666,000 |  | $ 26,688,000 | $ 35,421,000 | $ 37,871,000 |  |  |

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