5. Intangible and Other Assets, Net

Intangible and other assets, net, were comprised of the following at December 31:


*In thousands*	2012			2011
Capitalized patent and license costs	$	5,975		$	6,799
Purchased technology		—			5,901

		5,975			12,700
Less accumulated amortization		(4,982	)		(6,957	)

		993			5,743
Other assets		2,131			42

	$	3,124		$	5,785

Amortization expense for intangible assets was $218,000, $1.7 million and $0.9 million in 2012, 2011 and 2010, respectively. The weighted average amortization period for intangible assets was 17.0 years, 14.9 years and 14.8 years in 2012, 2011 and 2010, respectively. The estimated future amortization expense is $22,000 per year for 2013, 2014, 2015, 2016, and 2017 and $883,000 thereafter.

For the years ended December 31, 2012, 2011 and 2010, the Company recorded charges to operating expenses of $5.2 million, $312,000 and $2.4 million, respectively, to reflect impairment of the carrying value of certain capitalized patents and licenses or purchased technology. In 2012, the Company recorded a charge of $4.8 million to reflect impairment of the carrying value of intangible assets associated with ridaforolimus, the Company’s investigational oral mTOR inhibitor being developed by Merck following the decision in June 2012 by the FDA not to approve the NDA filed by Merck for the treatment of patients with soft tissue or bone sarcomas. In 2010, the charges relate to the write-off of the carrying value of patents related to the Company’s NF-kB technology, upon unsuccessful conclusion of litigation related to this technology, and an impairment of the carrying value of the ARGENT patents and certain other patents. The impairment of the carrying value of intangible assets was based on management’s assessment of the uncertainty related to the timing and amount of future cash flows anticipated from these assets.