Note 5 - Financial Instruments Measured at Fair Value - Short-term Investments by Security Type (Details) - USD ($) $ in Thousands		Mar. 30, 2024	Dec. 30, 2023
Amortized cost		$ 80,270	$ 90,100
Gross unrealized gains		80	215
Gross unrealized losses	[1]	93	141
Short-term investments		80,257	90,174
Estimated fair value		80,257	90,174
Corporate Debt Securities [Member]
Amortized cost	[2]	44,509	45,105
Gross unrealized gains	[2]	60	147
Gross unrealized losses	[1],[2]	28	15
Short-term investments	[2]	44,541	45,237
Estimated fair value	[2]	44,541	45,237
US Treasury Securities [Member]
Amortized cost		18,458	20,439
Gross unrealized gains		4	26
Gross unrealized losses	[1]	62	116
Short-term investments		18,400	20,349
Estimated fair value		18,400	20,349
Certificates of Deposit [Member]
Amortized cost		10,290	15,468
Gross unrealized gains		7	20
Gross unrealized losses	[1]	0	0
Short-term investments		10,297	15,488
Estimated fair value		10,297	15,488
Asset-Backed Securities [Member]
Amortized cost		5,953	8,017
Gross unrealized gains		7	17
Gross unrealized losses		3	10
Short-term investments		5,957	8,024
Estimated fair value		5,957	8,024
Debt Security, Government, Non-US [Member]
Amortized cost		730	741
Gross unrealized gains		0	0
Gross unrealized losses	[1]	0	0
Short-term investments		730	741
Estimated fair value		730	741
US States and Political Subdivisions Debt Securities [Member]
Amortized cost		330	330
Gross unrealized gains		2	5
Gross unrealized losses		0	0
Short-term investments		332	335
Estimated fair value		$ 332	$ 335

[1] As of March 30, 2024, the cost and fair value of investments with loss positions was approximately $44.7 million and $44.6 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 a credit loss exists. 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.