Annual report pursuant to Section 13 and 15(d)

Cover
- Document and Entity Information
Financial Statements
Notes to Financial Statements
Accounting Policies
- Summary of Significant Accounting Policies (Policies)
Notes Tables
Notes Details

Nature of Operations and Basis of Presentation - Additional Information (Details)

v3.19.1

Nature of Operations and Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Jun. 26, 2018 USD ($) $ / shares shares	May 30, 2018 USD ($) $ / shares shares	May 15, 2018 $ / shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 31, 2019 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Reverse share split			0.0636
Share consolidation basis nominal value per share \| $ / shares			$ 0.01571
Share consolidation basis, Renominalisation value per share \| $ / shares			$ 0.01
Net proceeds from issuance of stock after deducting underwriting discounts,commissions and offering cost	$ 2,400	$ 71,800		$ 74,153
Net losses				77,056	$ 29,406	$ 13,464
Accumulated deficit				131,793	54,737
Cash and cash equivalents				44,551	8,485
Short-term investments				40,000	$ 30,731
Cash resources available under the secured credit facility				$ 15,000
Scenario, Forecast
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cash resources available under the secured credit facility							$ 15,000
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued \| shares	200,000	6,150,000
Offering price per share \| $ / shares	$ 13.00	$ 13.00

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