Net Loss per Share - Instruments Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	21,061	20,791	21,061	20,791
Stock-based awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	21,061	16,791	21,061	16,791
Healios | Healios Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	0	4,000	0	4,000