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The cash inflow from the additional capital contribution to the entity.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Price of a single share of a number of saleable stocks of a company.

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Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Jul. 19, 2019	May 03, 2019	Jul. 03, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stockholders Equity Note Disclosure [Line Items]
Common stock, shares issued	1,587,000	3,144,531	2,807,017	52,078,258	43,917,378
Common stock issue price per share	$ 87.00	$ 64.00	$ 42.75
Exercised number of shares				87,663
Net proceeds from public offering	$ 131,100	$ 189,600	$ 129,300	$ 320,713		$ 129,309
Stock-based compensation expense				$ 12,847	$ 10,192	6,747
Stock options, outstanding				957,559	998,226
Aggregate intrinsic value of stock options exercised				$ 5,500	$ 5,300	$ 5,300
Weighted average grant date fair value of share-based awards granted				$ 31.27	$ 18.90	$ 16.94
Total fair value of stock options vested				$ 3,100	$ 2,300	$ 2,200
Total unrecognized compensation cost				$ 36,400
Unrecognized compensation cost, weighted average remaining requisite service period				4 years 1 month 2 days
Number of unvested options and restricted stock units				1,688,497
2018 Plan
Stockholders Equity Note Disclosure [Line Items]
Common stock shares reserved for Issuance					2,778,000
Incentive options, vesting period				2,555,281
Employee Stock Option \| Minimum \| Vest Over Three Year
Stockholders Equity Note Disclosure [Line Items]
Incentive options, vesting percentage				20.00%
Employee Stock Option \| Maximum \| Vest Over Five Year
Stockholders Equity Note Disclosure [Line Items]
Incentive options, vesting percentage				33.00%
Option To Purchase Common Stock
Stockholders Equity Note Disclosure [Line Items]
Stock options, outstanding				957,559	998,226	734,940
Restricted Stock Units (RSUs)
Stockholders Equity Note Disclosure [Line Items]
Restricted stock units, outstanding				734,984	705,413	505,235
Closing price of common stock				$ 92.50
Aggregate intrinsic value of restricted stock units vested				$ 17,500	$ 6,200	$ 4,000
Weighted average grant date fair value of restricted stock units granted				$ 49.68	$ 30.30	$ 26.03
Total grant date fair value of restricted stock units vested				$ 8,500	$ 4,600	$ 4,000
Underwriters \| Common Stock
Stockholders Equity Note Disclosure [Line Items]
Exercised number of shares	207,000	410,156	421,052