Accrued unvested common stock subject to repurchase current.

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- Definition

Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock.

+ References

No definition available.

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- Definition

Maximum shares allowed to be issued.

+ References

No definition available.

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- Definition

Maximum shares allowed to be issued under ESPP.

+ References

No definition available.

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- Definition

Stock options expiration period.

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No definition available.

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- Definition

Unvested common shares subject to repurchase outstanding.

+ References

No definition available.

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- Definition

Aggregate number of common shares reserved for future issuance.

+ References

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

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

+ References

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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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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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

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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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.

+ References

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-Publisher FASB
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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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
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- Definition

Number of share options (or share units) exercised during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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Stock Incentive Plans - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Jul. 31, 2017	Feb. 28, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total intrinsic value of options exercised	$ 391,913
Stock options exercised	26,204		0
Weighted-average grant date fair value of options granted	$ 8.44	$ 0.34
Remaining shares subject to repurchase	230,961		265,098
Liability for unvested common shares subject to repurchase included in accrued expenses and other liabilities	$ 107,135		$ 122,551
2015 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance				3,225,346	2,446,323
Stock option vesting period	4 years
Stock options expiration period	10 years
Number of shares outstanding available for future grant	453,176
Number of additional available for future grant	0
2018 Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance	3,186,205
Number of shares outstanding available for future grant	2,454,493
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock	4.00%
Maximum shares of common stock may be issued	20,887,347
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance	353,980
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock	1.00%
Maximum shares allowed to be issued under ESPP	4,778,738
2015 and 2018 Stock Incentive Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense	$ 9,500,000
Unrecognized compensation expense estimated to be recognized over period	3 years 7 months 24 days