Computation of Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerators:
Income (loss) from continuing operations	$ 22,003	$ 35,628	$ (16,909)
Consolidated loss from discontinued operations		(13)	(7,333)
Less: income attributable to noncontrolling interest			(10)
Loss from discontinued operations attributable to Novanta Inc.		(13)	(7,343)
Net income (loss) attributable to Novanta Inc.	$ 22,003	$ 35,615	$ (24,252)
Denominators:
Weighted average common shares outstanding—basic	34,694	34,579	34,352
Dilutive potential common shares	220	248
Weighted average common shares outstanding— diluted	34,914	34,827	34,352
Antidilutive common shares excluded from above	85		439
Basic Earnings (Loss) per Common Share:
From continuing operations	$ 0.63	$ 1.03	$ (0.49)
From discontinued operations		0.00	(0.21)
Basic earnings (loss) per share attributable to Novanta Inc.	0.63	1.03	(0.70)
Diluted Earnings (Loss) per Common Share:
From continuing operations	0.63	1.02	(0.49)
From discontinued operations		0.00	(0.21)
Diluted earnings (loss) per share attributable to Novanta Inc.	$ 0.63	$ 1.02	$ (0.70)