Clearwire 2009 Annual Report Download - page 62

We reco
g
n
i
ze compensat
i
on expense
f
or on
ly
t
h
e port
i
on o
f
stoc
k
opt
i
ons or RSUs t
h
at are expecte
d
to vest.
Therefore, we appl
y
an estimated forfeiture rate that is derived from historical emplo
y
ee termination behavior. If the
actua
l
num
b
er o
ff
or
f
e
i
tures
diff
ers
f
rom t
h
ose est
i
mate
db
y management, a
dj
ustments to stoc
k
-
b
ase
d
compensat
i
o
n
e
xpense may
b
e requ
i
re
di
n
f
uture per
i
o
d
s
.
Pro
p
ert
y
,P
l
ant & E
q
ui
p
men
t
As we continue to deploy our network, a significant portion of our total assets is PP&E. PP&E represented
$
2.6 billion of our
$
11.3 billion in total assets as of December 31, 2009. We
g
enerall
y
calculate depreciation on
t
hese assets usin
g
the strai
g
ht-line method based on estimated economic useful lives. The estimated useful life of
e
quipment is determined based on historical usa
g
e of identical or similar equipment, with consideration
g
iven t
o
t
ec
h
no
l
og
i
ca
l
c
h
anges an
di
n
d
ustry tren
d
st
h
at cou
ld i
mpact t
h
e networ
k
arc
hi
tecture an
d
asset ut
ili
zat
i
on. S
i
nce
c
han
g
es in technolo
gy
or in our intended use of these assets, as well as chan
g
es in broad economic or industr
y
factors, ma
y
cause the estimated period of use of these assets to chan
g
e, we periodicall
y
review these factors t
o
assess t
h
e rema
i
n
i
ng
lif
eo
f
our asset
b
ase. W
h
en t
h
ese
f
actors
i
n
di
cate t
h
at an asset’s use
f
u
l lif
e
i
s
diff
erent
f
rom t
he
p
revious assessment, we depreciate the remainin
g
book values prospectivel
y
over the ad
j
usted remainin
g
estimate
d
useful life
.
We ca
p
italize certain direct costs incurred to
p
re
p
are the asset for its intended use. We also ca
p
italize interest
assoc
i
ate
d
w
i
t
h
t
h
e acqu
i
s
i
t
i
on or construct
i
on o
f
networ
k
-re
l
ate
d
assets. Cap
i
ta
li
ze
di
nterest an
ddi
rect costs ar
e
r
eporte
d
as part o
f
t
h
e cost o
f
t
h
e networ
k
-re
l
ate
d
assets an
d
as a re
d
uct
i
on
i
nt
h
ere
l
ate
d
expense
i
nt
h
e statement o
f
o
p
erations
.
De
f
erre
d
Tax Asset Va
l
uation A
ll
owanc
e
Ava
l
uat
i
on a
ll
owance
i
s prov
id
e
df
or
d
e
f
erre
d
tax assets
if i
t
i
s more
lik
e
ly
t
h
an not t
h
at t
h
ese
i
tems w
ill
e
i
t
h
er
e
xpire before we are able to realize their benefit, or that future deductibilit
y
is uncertain. We record net deferred ta
x
assets to the extent we believe these assets will more likely than not be realized. In making such determination, w
e
c
ons
id
er a
ll
ava
il
a
bl
e pos
i
t
i
ve an
d
ne
g
at
i
ve ev
id
ence,
i
nc
l
u
di
n
g
our
li
m
i
te
d
operat
i
n
ghi
stor
y
,sc
h
e
d
u
l
e
d
reversa
l
so
f
deferred tax liabilities, pro
j
ected future taxable income/loss, tax plannin
g
strate
g
ies and recent financia
l
p
erformance
.
5
2
C
LEARWIRE
CO
RP
O
RATI
O
N AND
SU
B
S
IDIARIE
S
MANA
G
EMENT’
S
DI
SCUSS
I
O
N AND ANALY
S
I
SO
F FINAN
C
IAL
CO
NDITI
O
N
A
ND RESULTS OF OPERATIONS —
(
Continued
)