Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Cash flows from operating activities:
Net loss	$ (92,561)	$ (69,296)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	39	47
Stock-based compensation expense	17,112	8,786
Non-cash operating lease expense	197	249
Amortization of premiums and discounts on marketable securities, net	(655)	(1,229)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	672	6,637
Accounts payable	6,530	10,381
Accrued expenses	(17,385)	(8,280)
Operating lease liabilities	(101)	(303)
Other	0	(2)
Net cash used in operating activities	(86,152)	(53,010)
Cash flows from investing activities:
Purchases of property and equipment	(62)	0
Purchases of marketable securities	(486,782)	(117,057)
Maturities of marketable securities	142,569	65,993
Net cash used in investing activities	(344,275)	(51,064)
Cash flows from financing activities:
Payments of tax withholdings related to vesting of restricted stock units	(12,923)	(1,195)
Proceeds from exercise of stock options	1,119	560
Net cash provided by financing activities	609,431	54,269
Increase (decrease) in cash, cash equivalents and restricted cash	179,004	(49,805)
Cash, cash equivalents and restricted cash, beginning of period	357,745	215,788
Cash, cash equivalents and restricted cash, end of period	536,749	165,983
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	536,333	165,567
Restricted cash	416	416
Total cash, cash equivalents and restricted cash	536,749	165,983
Supplemental disclosures of non-cash activities:
Purchase of property and equipment included in accrued expenses	0	64
Right-of-use assets obtained in exchange for lease obligations	1,425	0
Removal of right-of-use assets in connection with lease termination	4,086	0
Follow-On Offering
Cash flows from financing activities:
Proceeds from stock offerings, net of issuance costs	621,235	0
At-The-Market Offering
Cash flows from financing activities:
Proceeds from stock offerings, net of issuance costs	$ 0	$ 54,904

Lease Termination, Derecognition Of Right-Of-Use Asset

No definition available.

Name:	prax_LeaseTerminationDerecognitionOfRightOfUseAsset
Namespace Prefix:	prax_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.