Company Overview - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cash and cash equivalents, restricted cash, and marketable securities	$ 34,600,000	$ 34,600,000
Accumulated deficit	682,800,000	$ 682,800,000	$ 659,469,000
Maturity limits period		24 months
Dollars weighted average maturity limit period		12 months
License Agreement Terms [Member] | Takeda License Agreements [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Upfront payment received	2,000,000
License Agreement Terms [Member] | Takeda License Agreements [Member] | Maximum [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Potential pre-commercialization payments receivable	57,000,000	$ 57,000,000
License Vosaroxin [Member] | Denovo Biopharma, LLC [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Upfront payment received	200,000
Potential regulatory and commercial payments receivable	$ 57,000,000	$ 57,000,000