Note 5 - Financial Instruments Measured at Fair Value - Short-term Investments by Security Type (Details) - USD ($) $ in Thousands		Dec. 28, 2024	Dec. 30, 2023
Amortized cost		$ 55,666	$ 90,100
Gross unrealized gains		62	215
Gross unrealized losses	[1]	43	141
Estimated fair value		55,685	90,174
Corporate Debt Securities [Member]
Amortized cost	[2]	32,040	45,105
Gross unrealized gains	[2]	37	147
Gross unrealized losses	[1],[2]	25	15
Estimated fair value	[2]	32,052	45,237
US Treasury Securities [Member]
Amortized cost		11,964	20,439
Gross unrealized gains		12	26
Gross unrealized losses	[1]	15	116
Estimated fair value		11,961	20,349
Certificates of Deposit [Member]
Amortized cost		6,971	15,468
Gross unrealized gains		4	20
Gross unrealized losses	[1]	3	0
Estimated fair value		6,972	15,488
Asset-Backed Securities [Member]
Amortized cost		3,647	8,017
Gross unrealized gains		6	17
Gross unrealized losses	[1]	0	10
Estimated fair value		3,653	8,024
Debt Security, Government, Non-US [Member]
Amortized cost		714	741
Gross unrealized gains		0	0
Gross unrealized losses	[1]	0	0
Estimated fair value		714	741
US States and Political Subdivisions Debt Securities [Member]
Amortized cost		330	330
Gross unrealized gains		3	5
Gross unrealized losses	[1]	0	0
Estimated fair value		$ 333	$ 335

[1] As of December 28, 2024, the cost and fair value of investments with loss positions were approximately $20.5 million and $20.4 million, respectively. As of December 30, 2023, the cost and fair value of investments with loss positions was approximately $38.5 million and $38.4 million, respectively. We evaluated the nature of these investments, credit worthiness of the issuer and the duration of these impairments to determine if an other-than-temporary decline in fair value had occurred and concluded that these losses were temporary and we have the ability and intent to hold these investments to maturity.

[2] Corporate debt securities include investments in financial and other corporate institutions. No single issuer represents a significant portion of the total corporate debt securities portfolio.