Common Stock, Capital Shares Reserved For Future Issuance, Percent of Outstanding Shares to be Added Annually

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- Definition

Number of Non-Employee Founders

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- Definition

Share-based Compensation Arrangement By Share-based Payment Award, Number Of Additional Shares Authorized, Maximum Annual Amount

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- Definition

Share-based Compensation Arrangement By Share-based Payment Award, Number Of Additional Shares Authorized, Percent Of Outstanding Shares

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- Definition

Aggregate number of common shares reserved for future issuance.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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 equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

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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- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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- Definition

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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Stock-based Compensation - Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended	12 Months Ended		61 Months Ended
	Jan. 01, 2018 shares	Feb. 28, 2013 shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) non-employee $ / shares shares	Dec. 31, 2017 non-employee shares	Jan. 31, 2017 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)			6,515,000	5,916,000	5,916,000	1,753,758
Weighted average fair value of options granted (in dollars per share) \| $ / shares			$ 12.88	$ 10.96
Intrinsic value of stock options exercised \| $			$ 5.7	$ 1.9
Unrecognized stock-based compensation expense, options \| $			$ 19.7
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)			7,000	16,000	16,000
Issued (in shares)			0
Vested (in shares)			9,000
Aggregate fair value of awards vested in period \| $			$ 0.1	$ 1.3
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)			371,000	0	0
Issued (in shares)			388,000
Vested (in shares)			0	0
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options \| $			$ 2.4
Remaining weighted average vesting period			1 year 7 months 13 days
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate			2.70%	2.10%
Expected dividend yield			0.00%	0.00%
Expected term (in years)			6 years 7 days	6 years 1 month 6 days
Expected volatility			65.20%	70.10%
Remaining weighted average vesting period			2 years 3 months 18 days
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)						0
Shares of common stock eligible to be purchased (in shares)						243,758
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)			1,113,539
Shares of common stock eligible to be purchased (in shares)						1,510,000
Percent of outstanding shares able to be added each year						4.00%
Number of additional shares authorized (in shares)	1,290,609
2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)						302,000
Number of additional shares authorized (in shares)	322,652
Percent of outstanding shares						1.00%
Maximum annual amount, shares authorized (in shares)						603,000
Founder Agreements \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issued (in shares)		1,395,659
Number of non-employee founders \| non-employee				2	2
Founder Agreements \| Restricted Stock \| Share-Based Compensation Award, Founder Awards, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares)					1,043,357
Founder Agreements \| Restricted Stock \| Share-Based Compensation Award, Founder Awards, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares)					352,302
Founder Agreements \| Restricted Stock \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Founder Agreements \| Restricted Stock \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years