Fair value
Estimated Useful Life
(in years)
Current assets
$23,344
N/A
Fixed assets
954
N/A
Customer relationships
37,800
7
Order backlog
6,800
2
Core/developed technology
35,200
4
Trade name
2,400
4
Deferred revenue
(14,700)
N/A
Deferred tax liability, net
(14,725)
N/A
Other liabilities
(1,120)
N/A
Goodwill
162,865
Indefinite
$238,818
2018 acquisition .
wombat security technologies inc .
on february 28 2018 -the “ wombat acquisition date ” pursuant to the terms of the merger agreement the company acquired all shares of wombat security technologies inc .
- “ wombat ” a leader for phishing simulation and security awareness computer-based training .
by collecting data from wombat ’ s phishalarm solution the company has access to data on phishing campaigns as seen by non-company customers providing broader visibility and insight to the proofpoint nexus platform .
with this acquisition the company ’ s customers can leverage the industry ’ s first solution combining the company ’ s advanced threat protection with wombat ’ s phishing simulation and computer-based security awareness training .
with the combined solutions the company ’ s customers can : .
use real detected phishing attacks for simulations assessing users based on the threats that are actually targeting them ; both investigate and take action on user-reporting phishing leveraging orchestration and automation to find real attacks quarantine emails in users ’ inboxes and lock user accounts to limit risk ; and train users in the moment immediately after they click for both simulated and real phishing attacks .
the company also expects to achieve savings in corporate overhead costs for the combined entities .
these factors among others contributed to a purchase price in excess of the estimated fair value of acquired net identifiable assets and as a result goodwill was recorded in connection with the acquisition .
proofpoint inc .
notes to consolidated financial statements -continued -dollars and share amounts in thousands except per share amounts .
at the wombat acquisition date the consideration transferred was $ 225366 net of cash acquired of $ 13452 .
per the terms of the merger agreement unvested in-the-money stock options held by wombat employees were canceled and paid off using the same amount per option as for the common share less applicable exercise price for each option .
the fair value of $ 1580 of these unvested options was attributed to pre-combination service and included in consideration transferred .
the fair value of unvested options of $ 1571 was allocated to post-combination services and expensed in the three months ended march 31 2018 .
also as part of the merger agreement 51 shares of the company ’ s common stock were deferred for certain key employees with the total fair value of $ 5458 -see note 11 “ equity award plans ” which was not included in the purchase price .
the deferred shares are subject to forfeiture if employment terminates prior to the lapse of the restrictions and their fair value is expensed as stock-based compensation expense over the remaining service period .
the following table summarizes the fair values of tangible assets acquired liabilities assumed intangible assets and goodwill : .

Question: How long is the estimated useful life for the Goodwill?
Answer: Indefinite