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Amount of cost to be recognized for option under share-based payment arrangement.

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

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

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Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions						12 Months Ended
	Mar. 18, 2020	Sep. 18, 2019	Aug. 03, 2018	May 14, 2018	Sep. 19, 2017	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
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			$ 42.7
Payments for Underwriting Expense			$ 3.3
Common stock, shares issued						10,095,176	10,087,363
Number of share outstanding						1,313,475	781,725
Awards granted under the plan						1,063,150
Unrecognized compensation expense						$ 5.6
Share based compensation arrangement by share based payment award, Average remaining vesting period						2 years 2 months 12 days
Weighted average grant date fair value of options granted						$ 8.03	$ 12.73
General and Administrative
Stockholders Equity [Line Items]
Stock based compensation expense						$ 1.6	$ 0.6
Research and Development
Stockholders Equity [Line Items]
Stock based compensation expense						$ 1.0	$ 0.7
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. On January 1, 2019, 403,495 additional shares were authorized according to the evergreen provision. At December 31, 2019, 162,004 shares of common stock remained available for the grant of future awards 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%
Available for the grant of future awards						162,004
Options contractual term				10 years
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 percentage Share-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 percentage Share-based compensation arrangement by share-based payment award, Vesting percentage				75.00%
2018 Stock Incentive Plan \| Executive Officers and Employees \| January 1, 2021
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentage Share-based compensation arrangement by share-based payment award, Vesting percentage		50.00%
2018 Stock Incentive Plan \| Executive Officers and Employees \| January 1, 2022
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentage Share-based compensation arrangement by share-based payment award, Vesting percentage		50.00%
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
Stockholders Equity [Line Items]
Common stock, shares issued						0
At-the-Market Facility \| Subsequent Event \| Maximum
Stockholders Equity [Line Items]
Aggregate offering price of common stock	$ 50.0