Note 12 - Stock-based Compensation (Tables)

12 Months Ended

Jan. 01, 2023

Notes Tables

Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Fiscal Years
Stock-based compensation expense included in:		2022		2021		2020
Cost of revenue	$	272	$	282	$	162
Research and development		652		843		670
Selling, general and administrative		1,111		1,401		907
Total costs and expenses	$	2,035	$	2,526	$	1,739

	Fiscal Years
Stock-based compensation expense by type of award:	2022		2021		2020
Stock options	$	—	$	—	$	39
ESPP		70		110		39
RSU and PRSU		1,965		2,416		1,661
Total costs and expenses	$	2,035	$	2,526	$	1,739

Share-Based Payment Arrangement, Activity [Table Text Block]

	Shares Available for Grant
Balance at January 3, 2021		320
Authorized		600
Options forfeited or expired		31
RSUs granted		(619	)
RSUs forfeited		262
Balance at January 2, 2022		594
Authorized		900
RSUs granted		(584	)
RSUs forfeited		50
Balance at January 1, 2023		960

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Term		Aggregate Intrinsic Value
	(in thousands)					(in years)		(in thousands)
Balance outstanding at December 29, 2019		186		$	32.09
Forfeited or expired		(65	)		38.83
Balance outstanding at January 3, 2021		121			28.46
Forfeited or expired		(28	)		31.68
Balance outstanding at January 2, 2022		93			27.49
Forfeited or expired		(18	)		39.72
Outstanding, exercisable, and vested at January 1, 2023		75		$	24.50		2.80	$	—

Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

	RSUs Outstanding
	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)
Nonvested at December 30, 2019		377		$	12.55
Granted		816			3.97
Vested		(144	)		10.41
Forfeited		(249	)		7.93
Nonvested at January 3, 2021		800			4.99
Granted		619			5.81
Vested		(586	)		4.99
Forfeited		(265	)		5.00
Nonvested at January 2, 2022		568			5.86
Granted		584			6.11
Vested		(490	)		5.56
Forfeited		(32	)		5.35
Nonvested at January 1, 2023		630		$	6.05

Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]

	Fiscal Years
	2022			2021			2020
Expected life (months)		6.0			6.0			6.0
Risk-free interest rate		3.04	%		0.05	%		0.12	%
Volatility		57	%		74	%		82	%
Dividend yield		—			—			—
Weighted average fair value of ESPP options granted	$	2.04		$	2.18		$	1.09