United states securities and exchange commission

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 15
Capitalization of Inventory Costs
We capitalize inventory costs associated with our products prior to regulatory approval, when, based on 
management’s judgment, future commercialization is considered probable and the future economic benefit is 
expected to be realized. We consider numerous attributes in evaluating whether the costs to manufacture a 
particular product should be capitalized as an asset. We assess the regulatory approval process and where the 
particular product stands in relation to that approval process, including any known safety or efficacy concerns, 
potential labeling restrictions and other impediments to approval. We evaluate our anticipated research and 
development initiatives and constraints relating to the product and the indication in which it will be used. We 
consider our manufacturing environment including our supply chain in determining logistical constraints that could 
hamper approval or commercialization. We consider the shelf life of the product in relation to the expected timeline 
for approval and we consider patent related or contract issues that may prevent or delay commercialization. We also 
base our judgment on the viability of commercialization, trends in the marketplace and market acceptance criteria. 
Finally, we consider the reimbursement strategies that may prevail with respect to the product and assess the 
economic benefit that we are likely to realize. We expense previously capitalized costs related to pre-approval 
inventory upon a change in such judgment, due to, among other potential factors, a denial or significant delay of 
approval by necessary regulatory bodies.
Obsolescence and Unmarketable Inventory
We periodically review our inventories for excess or obsolescence and write-down obsolete or otherwise 
unmarketable inventory to its estimated net realizable value. If the actual net realizable value is less than that 
estimated by us, or if it is determined that inventory utilization will further diminish based on estimates of demand, 
additional inventory write-downs may be required. Additionally, our products are subject to strict quality control and 
monitoring that we perform throughout the manufacturing process. In the event that certain batches or units of 
product no longer meet quality specifications, we will record a charge to cost of sales to write-down any 
unmarketable inventory to its estimated net realizable value. In all cases, product inventory is carried at the lower of 
cost or its estimated net realizable value. Amounts written-down due to unmarketable inventory are charged to cost 
of sales.
Property, Plant and Equipment
Property, plant and equipment are carried at cost, subject to review for impairment whenever events or changes 
in circumstances indicate that the carrying amount of the asset may not be recoverable. The cost of normal, 
recurring, or periodic repairs and maintenance activities related to property, plant and equipment are expensed as 
incurred. The cost for planned major maintenance activities, including the related acquisition or construction of 
assets, is capitalized if the repair will result in future economic benefits.
Interest costs incurred during the construction of major capital projects are capitalized until the underlying 
asset is ready for its intended use, at which point the interest costs are amortized as depreciation expense over the 
life of the underlying asset. We also capitalize certain direct and incremental costs associated with the validation 
effort required for licensing by regulatory agencies of new manufacturing equipment for the production of a 
commercially approved drug. These costs primarily include direct labor and material and are incurred in preparing the 
equipment for its intended use. The validation costs are either amortized over the life of the related equipment or 
expensed as cost of sales when the product produced in the validation process is sold.
In addition, we capitalize certain internal use computer software development costs. If the software is an 
integral part of production assets, these costs are included in machinery and equipment and are amortized on a 
straight-line basis over the estimated useful lives of the related software, which generally range from three to five 
years.

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Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued)
F- 16
We generally depreciate or amortize the cost of our property, plant and equipment using the straight-line 
method over the estimated useful lives of the respective assets, which are summarized as follows:
Asset Category
Useful Lives
Land
Not depreciated
Buildings
15 to 40 years
Leasehold Improvements
Lesser of the useful life or the term of the respective lease
Furniture and Fixtures
5 to 7 years
Machinery and Equipment
5 to 20 years
Computer Software and Hardware
3 to 5 years
When we dispose of property, plant and equipment, we remove the associated cost and accumulated 
depreciation from the related accounts in our consolidated balance sheets and include any resulting gain or loss in 
our consolidated statements of income.
Intangible Assets
Our intangible assets consist of acquired and in-licensed rights and patents, developed technology, out-licensed 
patents, in-process research and development acquired after January 1, 2009, trademarks and trade names. Our 
intangible assets are recorded at fair value at the time of their acquisition and are stated in our consolidated 
balance sheets net of accumulated amortization and impairments, if applicable.
Intangible assets related to acquired and in-licensed rights and patents, developed technology and out-licensed 
patents are amortized over their estimated useful lives using the economic consumption method if anticipated future 
revenues can be reasonably estimated. The straight-line method is used when revenues cannot be reasonably 
estimated. Amortization is recorded as amortization of acquired intangible assets in our consolidated statements of 
income.
Acquired and in-licensed rights and patents primarily relate to obtaining the fair value of the U.S. and rest of 
world licenses to Forward Pharma A/S' (Forward Pharma) intellectual property, including Forward Pharma's 
intellectual property related to TECFIDERA, and our acquisition of all remaining rights to TYSABRI from Elan Pharma 
International, Ltd. (Elan), an affiliate of Elan Corporation, plc. Developed technology primarily relates to our AVONEX 
product, which was recorded in connection with the merger of Biogen, Inc. and IDEC Pharmaceuticals Corporation in 
2003. We amortize the intangible assets related to TECFIDERA, TYSABRI and AVONEX using the economic 
consumption method based on revenues generated from the products underlying the related intangible assets. An 
analysis of the anticipated lifetime revenues of TECFIDERA, TYSABRI and AVONEX is performed annually during our 
long-range planning cycle, which is generally updated in the third quarter of each year, and whenever events or 
changes in circumstances would significantly affect the anticipated lifetime revenues of TECFIDERA, TYSABRI or 
AVONEX.
Intangible assets related to trademarks, trade names and in-process research and development prior to 
commercialization are not amortized because they have indefinite lives; however, they are subject to review for 
impairment. We review our intangible assets with indefinite lives for impairment annually, as of October 31, and 
whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable.

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