Stock-Based Compensation - Summary of Restricted Stock Units (Details) shares in Thousands	6 Months Ended
	Jun. 30, 2019 $ / shares shares
RSUs
RSUs
RSUs Outstanding at beginning of period (in shares) | shares	227
Granted (in shares) | shares	613
Vested (in shares) | shares	(75)
Forfeited (in shares) | shares	(81)
RSUs Outstanding at end of period (in shares) | shares	684
Weighted- Average Grant Date Fair Value (in dollars per share)
RSUs outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 23.02
Granted (in dollars per share) | $ / shares	20.04
Exercised (in dollars per share) | $ / shares	38.59
Forfeited (in dollars per share) | $ / shares	26.86
RSUs outstanding at the end of the period (in dollars per share) | $ / shares	$ 37.69
PSUs
RSUs
RSUs Outstanding at beginning of period (in shares) | shares	0
Granted (in shares) | shares	79
Vested (in shares) | shares	0
Forfeited (in shares) | shares	0
RSUs Outstanding at end of period (in shares) | shares	79
Weighted- Average Grant Date Fair Value (in dollars per share)
RSUs outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 19.20
Granted (in dollars per share) | $ / shares	19.20
Exercised (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	0
RSUs outstanding at the end of the period (in dollars per share) | $ / shares	$ 0