CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect Period of Adoption Adjustment	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect Period of Adoption Adjustment	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Accumulated Deficit Cumulative Effect Period of Adoption Adjustment
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	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 (Lease Accounting Standard) at Dec. 28, 2018		$ 113						$ 113
Balance (Nonemployee Share-Based Payment Standard) at Dec. 28, 2018					$ (315)			$ 315
Balance (in shares) at Dec. 28, 2018			44,195
Net income	14,048						14,048
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)			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
Net income	5,913						5,913
Other comprehensive loss	(2,497)					(2,497)
Common stock issued upon exercise of options	$ 20,646		$ 15	20,631
Common stock issued upon exercise of options (in shares)	1,507		1,507
Stock-based compensation	$ 13,275			13,275
Unvested restricted stock (in shares)	(11)		11
Vested restricted stock	$ 1		$ 1
Vested restricted stock (in shares)			108
Balance at Jan. 01, 2021	$ 197,222		$ 464	$ 338,194		$ (5,545)	$ (135,891)
Balance (in shares) at Jan. 01, 2021			46,448