Accounts That Went Negative

PayPal's risk team wants to flag accounts whose running balance ever dropped below zero. The balance after a transaction is the sum of all that account's transactions up to and including it, processed in order of `txn_date`, with `txn_id` breaking ties on the same date. Deposits are positive amounts and withdrawals are negative. Return `account_id`, `first_negative_date` (the date of the first transaction after which the balance was below zero) and `lowest_balance` (the minimum running balance reached) for every account that ever went below zero. Order the results by `account_id` ascending.