CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 30, 2016	$ 37,905	$ 407	$ 197,657	$ (1,050)	$ (159,109)
Balance (in shares) at Dec. 30, 2016		40,732
Net income (loss)	(2,139)				(2,139)
Other comprehensive loss	(100)			(100)
Common stock issued upon exercise of options	3,970	$ 6	3,964
Common stock issued upon exercise of options (in shares)		557
Stock-based compensation	3,533		3,533
Repurchase of employee common stock for taxes withheld	$ (234)		(234)
Repurchase of employee common stock for taxes withheld (in shares)		(24)
Unvested restricted stock (in shares)	(21)	21
Vested restricted stock	$ 1	$ 1
Vested restricted stock (in shares)		97
Balance at Dec. 29, 2017	42,936	$ 414	204,920	(1,150)	(161,248)
Balance (in shares) at Dec. 29, 2017		41,383
Net income (loss)	4,968				4,968
Other comprehensive loss	(170)			(170)
Proceeds from public offering of stock	72,150	$ 20	72,130
Proceeds from public offering of stock (in shares)		2,000
Common stock issued upon exercise of options	5,195	$ 6	5,189
Common stock issued upon exercise of options (in shares)		595
Stock-based compensation	7,399		7,399
Repurchase of employee common stock for taxes withheld	$ (54)		(54)
Unvested restricted stock (in shares)	(11)	11
Vested restricted stock	$ 2	$ 2
Vested restricted stock (in shares)		206
Balance at Dec. 28, 2018	132,426	$ 442	289,584	(1,320)	(156,280)
Balance (in shares) at Dec. 28, 2018		44,195
Net income (loss)	14,048				14,048
Impact of the adoption standard | Lease Accounting Standard	113				113
Impact of the adoption standard | Nonemployee Share-Based Payment Standard			(315)		315
Other comprehensive loss	(1,728)			(1,728)
Common stock issued upon exercise of options	$ 3,459	$ 4	3,455
Common stock issued upon exercise of options (in shares)	388	387
Stock-based compensation	$ 11,564		11,564
Unvested restricted stock (in shares)	(11)	11
Vested restricted stock	$ 2	$ 2
Vested restricted stock (in shares)		229
Balance at Jan. 03, 2020	$ 159,884	$ 448	$ 304,288	$ (3,048)	$ (141,804)
Balance (in shares) at Jan. 03, 2020		44,822