Beneficial ownership of common stock percentage forced conversion.

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Conversion Of Stock Conversion Price

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Convertible preferred stock beneficial ownership limitation percentage.

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Debt instrument convertible beneficial conversion feature intrinsic value.

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Employee service share based compensation non vested awards compensation cost to be recognized year

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Period ofNotice Prior to Conversion Allowed to Shareholders

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Share based compensation arrangement by share based payment award equity instruments other than options grants in period fair value.

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Share based compensation arrangement by share based payment award options granted in period fair value.

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Share based compensation arrangements by share based payment award term of options granted.

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Amount of decrease in additional paid in capital (APIC) resulting from dividends legally declared (or paid) in excess of retained earnings balance.

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Exercise price per share or per unit of warrants or rights outstanding.

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Number of warrants or rights outstanding.

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Face amount or stated value per share of common stock.

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

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The value of the stock converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Unrecognized cost of unvested share-based compensation awards.

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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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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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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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Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

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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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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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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Number of shares issued during the period as a result of the conversion of convertible securities.

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Number of shares issued in lieu of cash for services contributed to the entity. Number of shares includes, but is not limited to, shares issued for services contributed by vendors and founders.

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Stockholders' Equity - Additional information (Detail) - USD ($)		9 Months Ended
	May 17, 2018	Sep. 30, 2018	Aug. 02, 2018	Aug. 01, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested share-based compensation awards granted		$ 6,400,000
Unrecognized compensation cost related to non-vested share-based compensation awards granted year		2022
Stock option exercisable		1,711,966
Sale and issue of preferred stock, par value		$ 0.001
Common stock par value		$ 0.001			$ 0.001
Beneficial ownership limitation	9.98%
Adjustments to additional paid in capital dividends in excess of retained earnings		$ 12,500,000
Intrinsic Value of the conversion option		$ 12,500,000
Common shares, authorized		125,000,000	125,000,000	75,000,000	75,000,000
Warrant outstanding		2,136,020
Warrant exercise price per share		$ 2.60
Series B Non-Voting Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale and issue of preferred stock, par value		$ 0.001			$ 0.001
Series B preferred shares outstanding		3,100			0
Adjustments to additional paid in capital dividends in excess of retained earnings		$ 12,500,000
Series B Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock par value	$ 0.001
Conversion amount	$ 10,000
Conversion price	$ 1.80
Series B conversion to Common Stock	27,777,778	(1,900)
Equity Method Investment, Ownership Percentage	9.98%
Notice period	61 days
Series B preferred shares outstanding		3,100
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Series B conversion to Common Stock		10,555,556
William Blair And Company Llc [Member] \| Series B Non-Voting Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale and issue of preferred stock	5,000
Sale and issue of preferred stock, par value	$ 0.001
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments awarded in period		1,824,872
Vesting period of shares		3 years
Fair market value of RSUs granted		$ 4,200,000
Board of Directors and Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments awarded in period		2,260,211
Fair market value of shares granted		$ 3,300,000
Term of options granted period		10 years
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of shares		3 years
Employees [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments awarded in period		317,177
Board of Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of shares, Description		Options granted to members of the Board of Directors vest ratably through 2022