SQL & PL/SQL

Hello, I started 2409224 thread, and thought it got resolved. But when tested with actual (much bigger) data instead of test data, I got this error: ORA-01704 string literal too long error

Basically :memo variable below is coming from reporing environment's GUI control. Its supposed to contain IDs (10 character long), one per row. But thousands of them at once.

SELECT PHONE_NUMBER FROM TELEPHONE
WHERE ID IN
(
    SELECT REGEXP_SUBSTR(:memo,'\w+',1,LEVEL) ID
        FROM DUAL
    CONNECT BY
        LEVEL <= REGEXP_COUNT(:memo,'\w+',1)
)

How do I get rid of the exception? I've tried CASTing :memo to CLOB but then I get ORA-00932: inconsistent datatypes: expected - got CLOB