Equity Incentive Plans (Share-based Compensation Expense) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 1,590,000	$ 6,321,000	$ 3,997,000	$ 13,103,000
Research and development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	964,000	3,960,000	2,527,000	7,893,000
Selling, General and Administrative Expenses [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 626,000	$ 2,361,000	$ 1,470,000	$ 5,210,000