Basis of Presentation, Liquidity and Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock Options [Member]
Antidilutive securities excluded from computation of earnings per share, amount		15,374,000	8,990,000	15,103,000	8,990,000
Warrants [Member]
Antidilutive securities excluded from computation of earnings per share, amount	[1]		8,795,000		8,795,000
BioTime Warrants [Member]
Antidilutive securities excluded from computation of earnings per share, amount	[2]	1,296,000		917,000
Restricted Stock Units [Member]
Antidilutive securities excluded from computation of earnings per share, amount		271,000	535,000	275,000	535,000

[1] The warrants expired on October 1, 2018.

[2] Although the BioTime 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.