Note 5 - Financial Instruments Measured at Fair Value - Short-term Investments by Security Type (Details) - USD ($) $ in Thousands		Apr. 01, 2023	Dec. 31, 2022
Amortized cost		$ 98,087	$ 143,952
Gross unrealized gains		81	61
Gross unrealized losses	[1]	522	778
Short-term investments		97,646	143,235
Corporate Debt Securities [Member]
Amortized cost	[2]	36,670	59,283
Gross unrealized gains	[2]	23	30
Gross unrealized losses	[1],[2]	149	240
Short-term investments	[2]	36,544	59,073
Certificates of Deposit [Member]
Amortized cost		24,500	36,500
Gross unrealized gains		11	20
Gross unrealized losses	[1]	23	41
Short-term investments		24,488	36,479
US Treasury Securities [Member]
Amortized cost		23,137	34,614
Gross unrealized gains		47	1
Gross unrealized losses	[1]	286	418
Short-term investments		22,898	34,197
Asset-Backed Securities [Member]
Amortized cost		12,932	12,727
Gross unrealized gains		0	10
Gross unrealized losses	[1]	64	79
Short-term investments		12,868	12,658
Debt Security, Government, Non-US [Member]
Amortized cost		848	828
Gross unrealized gains		0	0
Gross unrealized losses	[1]	0	0
Short-term investments		$ 848	$ 828

[1] As of April 1, 2023, the cost and fair value of investments with loss positions was approximately $66.3 million and $65.8 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.