Stock-Based Compensation - Summary Of Changes In CSEs Outstanding (Details) - CSEs	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Common Stock Equivalents (CSEs)
Outstanding, Beginning Balance (in shares) | shares	110,013
Granted (in shares) | shares	5,550
Converted to shares of Common Stock upon grant (in shares) | shares	(5,783)
Outstanding, Ending Balance (in shares) | shares	109,780
Per Share Weighted Average Grant Date Fair Value
Outstanding, Beginning Balance (in Dollars per share) | $ / shares	$ 23.19
Granted (in Dollars per share) | $ / shares	131.49
Converted to shares of Common Stock upon grant (in Dollars per share) | $ / shares	93.45
Outstanding, Ending Balance (in Dollars per share) | $ / shares	$ 24.96