Stock-based Compensation - Stock Options (Details)	3 Months Ended
	Mar. 31, 2020 $ / shares shares
Shares
Outstanding at beginning of period (in shares) | shares	5,795,710
Granted (in shares) | shares	1,087,783
Exercised (in shares) | shares	(127,220)
Cancelled (in shares) | shares	(112,822)
Outstanding at end of period (in shares) | shares	6,643,451
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 58.82
Granted (in dollars per share) | $ / shares	57.21
Exercised (in dollars per share) | $ / shares	12.67
Cancelled (in dollars per share) | $ / shares	78.82
Outstanding at end of period (in dollars per share) | $ / shares	$ 59.10
Additional disclosures
Shares - Exercisable (in shares) | shares	2,863,027
Weighted-Average Exercise Price - Exercisable (in dollars per share) | $ / shares	$ 43.21