Note 13 - Stock-based Compensation (Tables)

12 Months Ended

Jan. 03, 2021

Notes Tables

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

	Fiscal Years
	2020		2019		2018
Cost of revenue	$	162	$	78	$	129
Research and development		670		2,242		760
Selling, general and administrative		907		824		1,012
Total costs and expenses	$	1,739	$	3,144	$	1,901

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

	Shares Available for Grant
Balance at December 29, 2019		272
Authorized		550
Options granted		—
Options forfeited or expired		65
RSUs granted		(816	)
RSUs forfeited		249
Balance at January 3, 2021		320

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 31, 2017		254		$	29.26		4.34
Granted		—			—
Forfeited or expired		(10	)		25.20
Exercised		(15	)		12.60
Balance outstanding at December 30, 2018		229			30.52		3.70
Granted		—			—
Forfeited or expired		(42	)		24.14
Exercised		(1	)		10.92
Balance outstanding at December 29, 2019		186			32.09		3.32
Granted		—			—
Forfeited or expired		(65	)		38.83
Exercised		—			—
Balance outstanding at January 3, 2021		121		$	28.46		3.75	$	—
Exercisable and Vested and expected to vest at January 3, 2021		121		$	28.46		3.75	$	—

Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]

	Options Outstanding						Options Exercisable
Range of Exercise Prices	Options Outstanding		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price		Options Vested and Exercisable		Weighted Average Exercise Price
	(in thousands)		(in years)				(in thousands)
$12.05		52		5.68	$	12.05		52	$	12.05
$18.48 - $31.50		14		2.82		26.71		14		26.71
$32.20		3		2.34		32.2		3		32.20
$38.92		14		0.85		38.92		14		38.92
$39.48 - $44.94		9		2.76		42.94		9		42.91
$46.62		3		3.34		46.62		3		46.62
$47.46		14		2.94		47.46		14		47.46
$48.72		8		1.35		48.72		8		48.72
$53.48		4		3.38		53.48		4		53.48
$12.05- $53.48		121		3.75	$	28.46		121	$	28.46

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

	RSUs & PRSUs Outstanding
	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)
Nonvested at December 31, 2017		168		$	21.56
Granted		110			11.90
Vested		(77	)		19.18
Forfeited		(18	)		—
Nonvested at December 30, 2018		183			17.22
Granted		353			10.77
Vested		(118	)		14.48
Forfeited		(41	)		—
Nonvested at December 29, 2019		377		$	12.55
Granted		816			3.97
Vested		(144	)		10.41
Forfeited		(249	)		7.93
Nonvested at January 3, 2021		800		$	4.99

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

	Fiscal Years
	2020			2019			2018
Expected life (months)		6.0			6.0			6.0
Risk-free interest rate		0.12	%		2.37	%		2.26	%
Volatility		82	%		54	%		50	%
Dividend yield		—			—			—