Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity (Details) - $ / shares
shares in Thousands |
12 Months Ended |
Dec. 31, 2021 |
Dec. 31, 2020 |
| Stock Option Plan of 2012 [Member] |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Number of Options Outstanding, Beginning balance |
15,865
|
14,710
|
| Number of RSUs Outstanding, Beginning balance |
93
|
166
|
| Weighted Average Exercise Price of Options Outstanding, beginning balance |
$ 1.57
|
$ 2.17
|
| Number of Options Outstanding, Options granted |
6,245
|
5,256
|
| Number of RSUs Outstanding, Options granted |
|
|
| Weighted Average Exercise Price of Options Outstanding, Options granted |
$ 2.50
|
$ 0.71
|
| Number of Options Outstanding, Options forfeited |
(3,146)
|
(4,101)
|
| Number of RSUs Outstanding, Options forfeited |
|
|
| Weighted Average Exercise Price of Options Outstanding, Options forfeited |
$ 1.99
|
$ 2.61
|
| Number of Options Outstanding, Restricted stock units vested |
|
|
| Number of RSUs Outstanding, Restricted stock units vested |
(62)
|
(73)
|
| Weighted Average Exercise Price of Options, Restricted stock units vested |
|
|
| Number of Options Outstanding, Options exercised |
(4,321)
|
|
| Number of RSUs Outstanding, Options exercised |
|
|
| Weighted Average Exercise Price of Options, Options exercised |
$ 1.72
|
|
| Number of Options Outstanding, Beginning balance |
14,643
|
15,865
|
| Number of RSUs Outstanding, Beginning balance |
31
|
93
|
| Weighted Average Exercise Price of Options Outstanding, beginning balance |
$ 1.84
|
$ 1.57
|
| Number of Options Outstanding, Options exercisable |
6,391
|
|
| Weighted Average Exercise Price of Options Outstanding, Options exercisable |
$ 1.68
|
|
| Number of Options Outstanding, Options forfeited |
3,146
|
4,101
|
| Asterias 2013 Equity Incentive Plan [Member] | Asterias Biotherapeutics Inc [Member] |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Number of Options Outstanding, Beginning balance |
350
|
350
|
| Number of RSUs Outstanding, Beginning balance |
|
|
| Weighted Average Exercise Price of Options Outstanding, beginning balance |
$ 1.57
|
$ 1.57
|
| Number of Options Outstanding, Options granted |
|
|
| Number of RSUs Outstanding, Options granted |
|
|
| Weighted Average Exercise Price of Options Outstanding, Options granted |
|
|
| Number of Options Outstanding, Options forfeited |
(109)
|
|
| Number of RSUs Outstanding, Options forfeited |
|
|
| Weighted Average Exercise Price of Options Outstanding, Options forfeited |
$ 1.57
|
|
| Number of Options Outstanding, Beginning balance |
241
|
350
|
| Number of RSUs Outstanding, Beginning balance |
|
|
| Weighted Average Exercise Price of Options Outstanding, beginning balance |
$ 1.57
|
$ 1.57
|
| Number of Options Outstanding, Options exercisable |
241
|
|
| Weighted Average Exercise Price of Options Outstanding, Options exercisable |
$ 1.57
|
|
| Number of Options Outstanding, Options forfeited |
109
|
|