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Basis of Presentation, Organization and Principal Activities - Liquidity Risks and Management's Plans (Details) $ / shares in Units, $ in Thousands	Mar. 26, 2021 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) person	Dec. 31, 2020 USD ($)
Description of Business and Basis of Presentation
Shares issued \| shares	15,853,658
Offering price per share \| $ / shares	$ 2.05
Gross proceeds from the offering	$ 32,500
Cash and cash equivalents		$ 60,357	$ 57,064
Minimum
Description of Business and Basis of Presentation
Number of hematology and oncology sales and marketing specialist \| person		100