Description of Business - Narrative (Details) - Sumitomo Dainippon Pharma, Co., Ltd. - Majority Shareholder - shares	Mar. 31, 2020	Dec. 27, 2019
Related Party Transaction [Line Items]
Number of shares owned (in shares)	46,788,604	45,008,604
Percentage of shares owned	52.10%	50.20%

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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