Summary of Significant Accounting Policies Equity Incentive Awards (Tables)

3 Months Ended

Mar. 31, 2022

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Abstract]

Schedule of Accrued Liabilities

Accrued liabilities: Accrued liabilities consisted of the following:

	As of March 31,		As of December 31,
	2022		2021
	(in thousands)
Accrued research and development services	$	5,308	$	3,669
Accrued compensation and benefits	2,616		5,711
Short term lease liability	940		1,089
Other	720		2,503
Total accrued liabilities	$	9,584	$	12,972

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Expected Volatility		Risk-free Interest Rate		Expected Term	Dividend Rate
March 31, 2022:
Employees	104	%	1.8	%	4	—	%
Officers and non-employee directors	91	%	1.9	%	7	—	%
March 31, 2021:
Employees	105	%	0.4	%	4	—	%
Officers and non-employee directors	90	%	1.0	%	7	—	%

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Options	Weighted Average Exercise Price
	(in thousands)
Outstanding at December 31, 2021	8,367	$	6.80
Granted	3,865	3.18
Expired	(140)	12.60
Forfeited	(308)	9.88
Outstanding at March 31, 2022	11,784	5.46
Exercisable at March 31, 2022	5,093	$	7.57

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

	Shares	Weighted Average Grant Date Fair Value
	(in thousands)
Outstanding at December 31, 2021	1,854	$	5.16
Granted	2,110	2.25
Vested	(980)	4.86
Forfeited	(35)	3.54
Outstanding at March 31, 2022	2,949	$	3.20