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Stockholders equity.

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Number of warrants or rights outstanding.

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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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Unrecognized cost of unvested options awarded to employees as compensation.

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Cash paid for expenses incurred during underwriting activities (the process to review insurance applications, evaluate risks, accept or reject applications, and determine the premiums to be charged) for insurance companies.

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The cash inflow associated with the amount received from entity's first offering of stock to the public.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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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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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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Date the equity-based award expires, in CCYY-MM-DD format.

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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).

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

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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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Number of options outstanding, including both vested and non-vested options.

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

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Percentage of vesting of share-based compensation awards.

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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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Number of new stock issued during the period.

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Stockholders' Equity - Additional Information (Details) - USD ($)								6 Months Ended
	Nov. 09, 2018	Aug. 03, 2018	May 14, 2018	Apr. 09, 2018	Jan. 29, 2018	Jan. 23, 2018	Sep. 19, 2017	Jun. 30, 2019	Dec. 31, 2018
Stockholders Equity [Line Items]
Stock issued during period, shares, new issues		2,555,555
Public offering price per share		$ 18.00
Proceeds from issuance initial public offering, after deduction underwriting discounts, commissions		$ 42,700,000
Payments for Underwriting Expense		$ 3,300,000
Number of share outstanding								983,506	781,725
Awards granted under the plan								563,150
Unrecognized compensation expense								$ 7,400,000
Share based compensation arrangement by share based payment award, Average remaining vesting period								3 years
Weighted average grant date fair value of options granted								$ 13.42
Warrants outstanding								0	0
Series J Warrants
Stockholders Equity [Line Items]
Warants expired for aggregate share of common stock to purrchase						2,942
Series K Warrants
Stockholders Equity [Line Items]
Warants expired for aggregate share of common stock to purrchase					2,262
Series M Warrants
Stockholders Equity [Line Items]
Warants expired for aggregate share of common stock to purrchase				301,452
2018 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance			500,000					403,495
Share-based compensation arrangement by share-based payment award, description								In addition, the number of shares authorized for issuance under the 2018 Plan is automatically increased (the “evergreen provision”) on the first day of each fiscal year beginning on January 1, 2019, and ending on (and including) January 1, 2028, in an amount equal to the lesser of (i) 4% of the outstanding shares of common stock on the last day of the immediately preceding fiscal year, or (ii) another amount (including zero) determined by the Company’s Board of Directors. Any shares subject to awards granted under the 2018 Plan that are forfeited or terminated before being exercised or settled, or are not delivered to the participant because such award is settled in cash, will again become available for issuance under the 2018 Plan. Shares withheld to satisfy the grant, exercise price or tax withholding obligation related to an award will again become available for issuance under the 2018 Plan.
Share-based compensation arrangement by share-based payment award, expiration date								Jan. 01, 2028
Share-based compensation arrangement by share-based payment award, percentage of outstanding our common stock								4.00%
Options contractual term			10 years
Available for the grant of future awards								485,973
2018 Stock Incentive Plan \| Executive Officers and Employees
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, stock options vesting period			4 years
2018 Stock Incentive Plan \| Executive Officers and Employees \| One-year Anniversary of the Grant Date
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentageShare-based compensation arrangement by share-based payment award, Vesting percentage			25.00%
2018 Stock Incentive Plan \| Executive Officers and Employees \| Quarterly over Remaining Three Years
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentageShare-based compensation arrangement by share-based payment award, Vesting percentage			75.00%
2013 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance							165,000
Options contractual term							10 years
Awards granted under the plan								0
2010 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance							470,170
Options contractual term							10 years
Awards granted under the plan								0
Maximum \| 2010 and 2013 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of share outstanding			635,170
Over-Allotment Option
Stockholders Equity [Line Items]
Stock issued during period, shares, new issues		333,333
At-the-Market Facility \| Maximum
Stockholders Equity [Line Items]
Aggregate offering price of common stock	$ 50,000,000