Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 99,278	$ 73,638
Short-term investments	160,027	126,092
Accounts receivable	24,928	25,144
Other receivables	0	33,775
Prepaid expenses and other current assets	5,859	5,237
Deferred tax assets	7,954	7,658
Total current assets	298,046	271,544
Patent assets, net	221,362	199,314
Property and equipment, net	3,639	3,144
Intangible assets, net	2,458	3,226
Goodwill	16,460	16,460
Other assets	838	279
Total assets	542,803	493,967
Current liabilities:
Accounts payable	698	568
Accrued liabilities	5,118	7,206
Deferred revenue	111,744	101,249
Deferred payment obligations	500	500
Other current liabilities	1,565	1,813
Total current liabilities	119,625	111,336
Deferred revenue, less current portion	5,829	3,122
Deferred tax liabilities	17,430	18,108
Other liabilities	2,185	1,142
Total liabilities	145,069	133,708
Common stock	5	5
Additional paid-in capital	293,555	281,530
Retained earnings	104,136	78,744
Accumulated other comprehensive income (loss)	38	(20)
Total stockholders' equity	397,734	360,259
Total liabilities and stockholders' equity	$ 542,803	$ 493,967