CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total		Common Shares	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2017	$ 311,545		$ 423,856	$ 33,309	$ (17,880)	$ (127,740)
Balance (in shares) at Dec. 31, 2017			34,595
Net income	11,911	[1]				11,911
Redeemable noncontrolling interest redemption value adjustment	(5,399)	[1]				(5,399)
Common stock issued under stock plans (in shares)			141
Shares withheld for taxes on vested stock awards	(2,804)			(2,804)
Shares withheld for taxes on vested stock awards (in shares)			(51)
Share-based compensation	2,044			2,044
Adoption of ASU 2016-16 | ASU 2016-16	(2,242)					(2,242)
Other comprehensive income (loss), net of tax	3,555				3,555
Balance at Mar. 30, 2018	318,610		$ 423,856	32,549	(14,325)	(123,470)
Balance (in shares) at Mar. 30, 2018			34,685
Balance at Dec. 31, 2018	368,255		$ 423,856	46,018	(22,527)	(79,092)
Balance (in shares) at Dec. 31, 2018			34,886
Net income	12,253	[2]				12,253
Common stock issued under stock plans (in shares)			186
Shares withheld for taxes on vested stock awards	(5,890)			(5,890)
Shares withheld for taxes on vested stock awards (in shares)			(74)
Share-based compensation	2,727			2,727
Other comprehensive income (loss), net of tax	2,356				2,356
Balance at Mar. 29, 2019	$ 379,701		$ 423,856	$ 42,855	$ (20,171)	$ (66,839)
Balance (in shares) at Mar. 29, 2019			34,998

[1] 53,968 non-GAAP EPS performance restricted stock units granted to certain members of the executive management team were considered contingently issuable shares and were excluded from the calculation of the denominator as the contingent conditions had not been met as of March 30, 2018.

[2] 45,252 non-GAAP EPS performance restricted stock units granted to certain members of the executive management team and 213,219 shares of restricted stock issued to Laser Quantum former non-controlling interest holders are considered contingently issuable shares and are excluded from the calculation of the denominator as the contingent conditions had not been met as of March 29, 2019.