Share Based Compensation Arrangement By Share Based Payment Award Options Vested Grant Date Fair Value

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- Definition

Aggregate number of common shares reserved for future issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

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- Definition

General descriptive information regarding an arrangement under which employees and directors receive: (a) awards of equity shares, equity share options, or other equity instruments; or (b) the entity incurs liabilities to them: (1) in amounts based, at least in part, on the price of the entity's shares or other equity instruments; or (2) that require or may require settlement by issuance of the entity's shares. Such an arrangement is usually provided to employees and directors to compensate them, provide performance incentives to them, and to attract or retain their services. May also include pertinent information particular to a plan that is not elsewhere specified in the taxonomy.

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-Topic 718
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- Definition

Discount rate from fair value on offering date that participants pay for shares.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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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.

+ References

No definition available.

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- Definition

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

+ References

No definition available.

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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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 718
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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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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- Definition

Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

+ References

No definition available.

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- Definition

Number of share instruments newly issued under a share-based compensation plan.

+ References

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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-Publisher FASB
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Stock-Based Compensation - Additional Information (Detail) - USD ($)			3 Months Ended		6 Months Ended
	Jul. 15, 2015	Jul. 14, 2015	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares reserved for issuance			11,681,221		11,681,221		9,674,371
2015 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares reserved for issuance	700,000		700,000		700,000		700,000
Stock option grants description					The number of shares initially reserved for issuance under the ESPP will increase automatically on January 1 for nine years from the first offering date by the number of shares equal to 1% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31.
Percentage threshold of outstanding shares increased annually under the plan	1.00%
Common shares authorized to be issued during the period	3,400,000
Options to purchase shares of common stock, discount percentage	15.00%
Number of common stock issued					0
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares reserved for issuance			8,628,047		8,628,047
Stock option grants description					The number of shares reserved for issuance under the 2015 Plan will increase automatically on January 1 of each calendar year 2016 through 2025 by the number of shares equal to 4% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31.
Percentage threshold of outstanding shares increased annually under the plan		4.00%
Stock option life in years					10 years
2008 Plan and 2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares reserved for issuance			411,262		411,262		1,503,770
Weighted-average grant date fair values of options granted			$ 1.87	$ 0.80	$ 1.78	$ 1.08
Aggregate intrinsic value of options exercised			$ 35,000	$ 0	$ 200,000	$ 100,000
Total grant date fair value of options vested			1,400,000	$ 1,600,000	3,100,000	$ 3,800,000
Total unrecognized stock-based compensation related to unvested stock options			$ 11,600,000		$ 11,600,000
Weighted-average period					2 years 2 months 12 days
Common shares authorized to be issued during the period					2,095,808