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Stock Option Plans - Narrative (Details) - $ / shares	3 Months Ended
Stock Option Plans - Narrative (Details) - $ / shares	Mar. 31, 2019	Mar. 29, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option expiration period	10 years
Option vesting period	4 years
Closing share price (in usd per share)		$ 51.37
Granted (in shares)	1,106,669		1,114,169
Weighted average remaining contractual life of the Company's outstanding options	6 years 11 months 26 days
Weighted average remaining contractual life of the Company's exercisable options	5 years 11 months 17 days
2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		210,875
2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		227,500