Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Other prepaid expenses		$ 500
Other current assets	$ 1,410	1,843
Prepaid Expenses [Member]
Other current assets	1,400	1,800
Prepaid Expenses [Member] | BP1002 in lymphoma, prexigebersen in AML and prexigebersen-A [Member]
Other current assets	1,000	1,400
Other Prepaid Expenses [Member] | BP1002 in lymphoma, prexigebersen in AML and prexigebersen-A [Member]
Other prepaid expenses		100
Prepaid manufacturing development expense	300
Prepaid insurance	$ 100	$ 300