Common Stock, Capital Shares Reserved for Future Issuance, Annual Increase, Percentage of Outstanding Common Stock

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period, Achievement Percentage

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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- Definition

Aggregate number of common shares reserved for future issuance.

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- Definition

Face amount or stated value per share of common stock.

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- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

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- Definition

Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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- Definition

Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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- Definition

The number of grants made 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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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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- Definition

Gross number of share options (or share units) granted during the period.

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Number of shares issued under share-based payment arrangement.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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No definition available.

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Equity and Employee Stock Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended
	Jun. 01, 2019	Jul. 27, 2017	Jul. 26, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, authorized (in shares)				500,000,000		500,000,000		500,000,000
Common stock, par value (in dollars per share)				$ 0.001		$ 0.001		$ 0.001
Preferred stock, shares authorized (in shares)				10,000,000		10,000,000		10,000,000
Preferred stock, par value (in dollars per share)				$ 0.001		$ 0.001		$ 0.001
Preferred stock, shares outstanding (in shares)				0		0		0
Preferred stock, shares issued (in shares)				0		0		0
Unrecognized stock-based compensation, options				$ 4,092		$ 4,092
Options granted (in shares)						150,000
Options granted (in dollars per share)						$ 27.50
Share-based payment expense				$ 7,510	$ 5,498	$ 19,792	$ 14,473
Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved (in shares)			7,898,159	20,476,766		20,476,766		17,768,064
Percentage of common stock, outstanding			5.00%
Restricted stock units outstanding (in shares)				4,536,677		4,536,677		3,264,702
2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved (in shares)				2,628,863		2,628,863		1,989,460
Shares issued under ESPP (in shares)				262,110		262,110
Employee stock purchase plan shares \| 2004 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved (in shares)				0		0
Employee stock purchase plan shares \| 2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved (in shares)		1,600,000
Percentage of common stock, outstanding		1.00%
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, period for recognition						1 year 3 months
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, period for recognition						3 years 29 days
Unrecognized stock-based compensation				$ 76,009		$ 76,009
Restricted stock units granted (in shares)						2,102,975
Restricted stock units outstanding (in shares)				4,536,677		4,536,677		3,264,702
Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units outstanding (in shares)				279,826		279,826
Achievement percentage of performance conditions						100.00%
Share-based payment expense						$ (126)
Chief Executive Officer \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	150,000
Options granted (in dollars per share)	$ 27.50
Maximum \| Chief Executive Officer \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	300,000
January to December 2019 Awards \| Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment expense						(610)
January to June 2019 Awards \| Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment expense						$ 484