Summary of Significant Accounting Policies Equity Incentive Awards (Tables)

9 Months Ended

Sep. 30, 2021

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 September 30,		As of December 31,
	2021		2020
	(in thousands)
Accrued research and development services	$	7,544	$	21,962
Accrued compensation and benefits	4,172		6,200
Short term lease liability	1,027		553
Other	1,465		976
Total accrued liabilities	$	14,208	$	29,691

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

	Expected Volatility		Risk-free Interest Rate		Expected Term	Dividend Rate
September 30, 2021:
Employees	102	%	0.6	%	4	—	%
Officers and non-employee directors	90	%	1.1	%	7	—	%
September 30, 2020:
Employees	91	%	1.3	%	4	—	%
Officers and non-employee directors	78	%	1.4	%	8	—	%

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

	Options	Weighted Average Exercise Price
	(in thousands)
Outstanding at December 31, 2020	8,397	$	7.12
Granted	1,448	6.88
Exercised	(281)	4.31
Expired	(191)	12.50
Forfeited	(733)	8.92
Outstanding at September 30, 2021	8,640	6.90
Exercisable at September 30, 2021	5,092	$	8.16

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

	Shares	Weighted Average Grant Date Fair Value
	(in thousands)
Outstanding at December 31, 2020	2,769	$	4.35
Granted	663	8.22
Vested	(1,239)	5.04
Forfeited	(217)	4.96
Outstanding at September 30, 2021	1,976	$	5.15