Note 5 - Financial Instruments Measured at Fair Value - Short-term Investments by Security Type (Details) - USD ($) $ in Thousands		Jul. 01, 2023	Dec. 31, 2022
Amortized cost		$ 97,529	$ 143,952
Gross unrealized gains		10	61
Gross unrealized losses	[1]	512	778
Short-term investments		97,027	143,235
Corporate Debt Securities [Member]
Amortized cost	[2]	40,643	59,283
Gross unrealized gains	[2]	5	30
Gross unrealized losses	[1],[2]	113	240
Short-term investments	[2]	40,535	59,073
Certificates of Deposit [Member]
Amortized cost		21,250	36,500
Gross unrealized gains		4	20
Gross unrealized losses	[1]	21	41
Short-term investments		21,233	36,479
US Treasury Securities [Member]
Amortized cost		21,179	34,614
Gross unrealized gains		0	1
Gross unrealized losses	[1]	323	418
Short-term investments		20,856	34,197
Asset-Backed Securities [Member]
Amortized cost		10,644	12,727
Gross unrealized gains		0	10
Gross unrealized losses	[1]	55	79
Short-term investments		10,589	12,658
US Government-sponsored Enterprises Debt Securities [Member]
Amortized cost		2,980
Gross unrealized gains		1
Gross unrealized losses	[1]	0
Short-term investments		2,981
Debt Security, Government, Non-US [Member]
Amortized cost		833	828
Gross unrealized gains		0	0
Gross unrealized losses	[1]	0	0
Short-term investments		$ 833	$ 828

[1] As of July 1, 2023, the cost and fair value of investments with loss positions was approximately $76.8 million and $76.2 million, respectively. As of December 31, 2022, the cost and fair value of investments with loss positions was approximately $86.3 million and $85.5 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.