Computation of Basic and Diluted Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017		Jul. 01, 2016
Numerators:
Income from continuing operations	$ 9,990	$ 4,871	$ 44,264		$ 6,777
Less: Net income attributable to noncontrolling interest	(588)		(610)
Net income attributable to Novanta Inc.	9,402	4,871	43,654		6,777
Less: Adjustment of redeemable noncontrolling interest to estimated redemption value (see Note 14)	(3,718)		(3,718)	[1]
Net income attributable to Novanta Inc. after adjustment of redeemable noncontrolling interest to estimated redemption value	$ 5,684	$ 4,871	$ 39,936		$ 6,777
Denominators:
Weighted average common shares outstanding—basic	34,827	34,734	34,796		34,696
Dilutive potential common shares	636	153	498		174
Weighted average common shares outstanding— diluted	35,463	34,887	35,294		34,870
Antidilutive common shares excluded from above		193			97
Basic Earnings per Common Share:
Basic earnings per common share attributable to Novanta Inc.	$ 0.16	$ 0.14	$ 1.15		$ 0.20
Diluted Earnings per Common Share:
Diluted earnings per common share attributable to Novanta Inc.	$ 0.16	$ 0.14	$ 1.13		$ 0.19

[1] Adjustment of the carrying value of redeemable noncontrolling interest to the estimated redemption value was recognized in retained earnings instead of the consolidated statement of operations but was included in the computation of earnings per share attributable to Novanta Inc. (see Note 5.)