Leases

(a) Capital Leases

The following is an analysis of the leased property under capital leases by major class (in thousands):



	Asset balances at December 31,
Class of property	2012		2011
Lab equipment	$	489	$	489
Leasehold improvements	27		27
Total property under capital leases	516		516
Less accumulated depreciation and amortization	211		137
Capital leased assets, net	$	305	$	379

The depreciation and amortization reflected above has been recorded as depreciation and amortization expense in these consolidated financial statements.

The following is a schedule by years of the future minimum lease payments under capital leases together with the present value of the net minimum lease payments as of December 31, 2012 (in thousands):



Year ending December 31:
2013	$	60
2014	19
2015	18
2016	4
Total minimum lease payments	101
Less amount representing interest	8
Present value of net minimum lease payments	$	93

(b) Operating Leases

The Company has certain facilities operating leases that are being leased on a month-to-month basis. The Company entered into a new lease for additional space in October 2009 expiring in 2015. Under the terms of the lease, the Company has the option to extend the lease for three additional five-year periods upon the same terms as the base lease. Additionally, in November of 2011, the Company entered into an amendment to the October 2009 lease adding additional space and extending the term through 2017. The Company also leases laboratory space from one of its licensors. Lease expense is recognized on a straight-line basis. Rental expense for operating leases during the years ended December 31, 2012, 2011 and 2010, and from inception through December 31, 2012, was $707,000, $601,000, $601,000 and $3.7 million respectively.

Future minimum lease payments under the noncancelable operating leases (with initial or remaining lease terms in excess of one year) as of December 31, 2012 are as follows (in thousands):



Year ending December 31:
2013	$	484
2014	441
2015	193
2016	170
2017	29
	$	1,317