Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 78,019	$ 100,155
Short-term investments	239,514	190,567
Restricted cash	584	364
Accounts receivable	24,793	38,477
Prepaid expenses and other current assets	3,466	10,546
Deferred tax assets	4,400	3,817
Total current assets	350,776	343,926
Patent assets, net	236,349	219,954
Property and equipment, net	4,151	4,667
Intangible assets, net	3,526	1,718
Goodwill	19,978	16,460
Restricted cash, less current portion	1,091	1,454
Other assets	26,100	622
Deferred Tax Assets, Net, Noncurrent	93	0
Total assets	642,064	588,801
Current liabilities:
Accounts payable	235	332
Accrued liabilities	14,257	8,784
Deferred revenue	133,316	131,808
Deferred payment obligations	0	500
Other current liabilities	640	1,638
Total current liabilities	148,448	143,062
Deferred revenue, less current portion	2,893	5,935
Deferred tax liabilities, less current portion	0	11,654
Other liabilities	5,678	3,227
Total liabilities	157,019	163,878
Common stock	5	5
Additional paid-in capital	326,280	305,343
Retained earnings	158,868	119,527
Accumulated other comprehensive income (loss)	(108)	48
Total stockholders' equity	485,045	424,923
Total liabilities and stockholders' equity	$ 642,064	$ 588,801