Intangible assets, net (Tables)

3 Months Ended

Mar. 31, 2013

Intangible assets [Abstract]

Summary of intangible assets

	March 31, 2013							December 31, 2012
	Gross carrying amount		Accumulated amortization			Net carrying amount		Gross carrying amount		Accumulated amortization			Net carrying amount
Licensed intellectual property	$	3,942	$	(1,376	)	$	2,566	$	3,144	$	(1,312	)	$	1,832

Summary of estimated future amortization expense

Years Ending March 31,	Amount
2014	$	311
2015		311
2016		311
2017		306
2018		302
Thereafter		1,025
Total	$	2,566