4.	Intangible and Other Assets, Net

Intangible and other assets, net, were comprised of the following at September 30, 2012 and December 31, 2011:


*In thousands*	September 30, 2012			December 31, 2011
Capitalized patent and license costs	$	5,992		$	6,799
Purchased technology		—			5,901

		5,992			12,700
Less accumulated amortization		(4,977	)		(6,957	)

		1,015			5,743
Other assets		1,933			42

	$	2,948		$	5,785

Amortization expense for intangible assets amounted to $4,000 and $728,000 for the three-month periods ended September 30, 2012 and 2011, respectively, and amounted to $213,000 and $1.3 million for the nine-month periods ended September 30, 2012 and 2011, respectively. The weighted average amortization period for intangible assets was 17.0 years in 2012 and 15.3 years in 2011.

In addition to amortization expense, during the nine-month period ended September 30, 2012, the Company recorded charges to operating expenses 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 & Co., Inc. (“Merck”) for oncology indications pursuant to a license with the Company, following the decision in June 2012 by the U.S. Food and Drug Administration (“FDA”) to not approve the New Drug Application (“NDA”) filed by Merck for the treatment of patients with soft tissue or bone sarcomas, stating that additional clinical trial(s) would need to be conducted to further assess safety and efficacy of ridaforolimus in this indication. The impairment of the carrying value of ridaforolimus 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.