DEFERRED GRANT INCOME (Details) - USD ($)
$ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2019
Dec. 31, 2018
Jul. 31, 2017
Grants Receivable     $ 15,912
California Institute Of Regenerative Medicine [Member]      
Proceeds from Grantors $ 12,550 $ 9,050  
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned $ 3,290 $ 6,267