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. 28, 2019	[1]	Jun. 29, 2018		Jun. 28, 2019	[1]	Jun. 29, 2018
Numerators:
Consolidated net income		$ 10,380		$ 11,625	[2]	$ 22,633		$ 24,462	[2]
Less: Net income attributable to noncontrolling interest	[2]			(625)				(1,551)
Net income attributable to Novanta Inc.		10,380		11,000	[2]	22,633		22,911	[2]
Redeemable noncontrolling interest redemption value adjustment	[2]			303				(5,096)
Net income attributable to Novanta Inc. after adjustment for redeemable noncontrolling interest redemption value		$ 10,380		$ 11,303	[2]	$ 22,633		$ 17,815	[2]
Denominators:
Weighted average common shares outstanding—basic		34,998		34,949	[2]	34,981		34,919	[2]
Dilutive potential common shares		505		525	[2]	510		532	[2]
Weighted average common shares outstanding— diluted		35,503		35,474	[2]	35,491		35,451	[2]
Antidilutive potential common shares excluded from above		36				47		6	[2]
Earnings per Common Share Attributable to Novanta Inc.:
Basic		$ 0.30		$ 0.32	[2]	$ 0.65		$ 0.51	[2]
Diluted		$ 0.29		$ 0.32	[2]	$ 0.64		$ 0.50	[2]

[1] 45,252 non-GAAP EPS performance-based 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 June 28, 2019.

[2] 53,968 non-GAAP EPS performance-based 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 June 29, 2018.