Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount		17,692,000	15,374,000	16,054,000	15,103,000
Lineage Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	[1]	1,090,000	1,296,000	1,090,000	917,000
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount		139,000	271,000	150,000	275,000

[1] Although the Lineage Warrants are classified as liabilities, these warrants are considered for dilutive earnings per share calculations in accordance with ASC 260, Earnings Per Share, and determined to be anti-dilutive for the period presented.