Millendo Merger (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 25, 2021
Business Acquisition [Line Items]
Cash and cash equivalents	$ 59,716,000		$ 18,820,000	$ 59,716,000	$ 18,820,000
Operating lease right-of-use assets	3,357,000		1,877,000	3,357,000	1,877,000
Present value of operating lease obligations	3,809,000			3,809,000
Stock-based compensation expense	296,000		91,000	827,000	321,000
General and Administrative Expense
Business Acquisition [Line Items]
Stock-based compensation expense	191,000		$ 32,000	600,000	$ 31,000
Private Tempest
Business Acquisition [Line Items]
Cash and cash equivalents						$ 17,000,000
Prepaid Expense and Other Assets						1,400,000
Accrued Liabilities and Other Liabilities						500,000
Operating lease right-of-use assets						2,100,000
Present value of operating lease obligations						$ 2,100,000
Private Tempest | General and Administrative Expense
Business Acquisition [Line Items]
Stock-based compensation expense		$ 200,000
Private Tempest | Additional Paid-in Capital
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs	$ 6,400,000			$ 6,400,000