CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Consolidated net income		$ 44,521	[1]	$ 40,773	[2]	$ 51,095	[3]
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax	[4]	6,922		3,267		(4,172)
Pension liability adjustments, net of tax	[5]	(1,050)		1,147		(475)
Total other comprehensive income (loss)		5,872		4,414		(4,647)
Total consolidated comprehensive income		50,393		45,187		46,448
Less: Comprehensive income attributable to noncontrolling interest						(1,986)
Comprehensive income attributable to Novanta Inc.		$ 50,393		$ 45,187		$ 44,462

[1] For the year ended December 31, 2020, 45 non-GAAP EPS performance-based restricted stock units granted to certain members of the executive management team and 213 shares of restricted stock issued to Laser Quantum former non-controlling interest shareholders are considered contingently issuable shares and were excluded from the calculation of the denominator as the contingent conditions had not been met as of December 31, 2020.

[2] For the year ended December 31, 2019, 46 non-GAAP EPS performance-based restricted stock units granted to certain members of the executive management team and 213 shares of restricted stock issued to Laser Quantum former non-controlling interest shareholders were considered contingently issuable shares and were excluded from the calculation of the denominator as the contingent conditions had not been met as of December 31, 2019.

[3] For the year ended December 31, 2018, 54 non-GAAP EPS performance-based restricted stock units granted to certain members of the executive management team and 213 shares of restricted stock issued to Laser Quantum former non-controlling interest shareholders were considered contingently issuable shares and were excluded from the calculation of the denominator as the contingent conditions had not been met as of December 31, 2018.

[4] The tax effect on this component of comprehensive income was $0, $3 and ($93) in 2020, 2019 and 2018, respectively.

[5] The tax effect on this component of comprehensive income was ($202), $267 and ($153) in 2020, 2019 and 2018, respectively.