Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022
Statement of Cash Flows [Abstract]
Related parties accounts payable and accrued expenses	$ 264	$ 1,102

Increase (decrease) in accounts payable and accrued expenses related parties.

No definition available.

Name:	phat_IncreaseDecreaseInAccountsPayableAndAccruedExpensesRelatedParties
Namespace Prefix:	phat_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration