Stock-Based Compensation - Summary of Stock Option Activity (Details)	3 Months Ended
	Mar. 31, 2020 $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Beginning Balance | shares	3,887,780
Options Outstanding, Options granted | shares	1,279,300
Options Outstanding, Options forfeited | shares	(8,000)
Options Outstanding, Options exercised | shares	(72,833)
Options Outstanding, Ending Balance | shares	5,086,247
Options Outstanding, Vested and expected to vest | shares	5,086,247
Options Outstanding, Exercisable as of March 31, 2020 | shares	2,483,500
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 18.38
Weighted Average Exercise Price, Options granted | $ / shares	67.08
Weighted Average Exercise Price, Options forfeited | $ / shares	30.03
Weighted Average Exercise Price, Options exercised | $ / shares	6.89
Weighted Average Exercise Price, Ending Balance | $ / shares	30.78
Weighted Average Exercise Price, Vested and expected to vest | $ / shares	30.78
Weighted Average Exercise Price, Exercisable as of March 31, 2020 | $ / shares	$ 11.12