Components of Tax Effects of Significant Temporary Differences that give Rise to the Net Deferred Tax Asset (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Deferred Tax Liability Not Recognized [Line Items]
Federal net operating loss carryforwards	$ 137,736	$ 133,454
State net operating loss carryforwards	53,815	53,350
Stock-based compensation expense	27,775	26,771
Accrued liabilities	26,299	29,600
Asset impairment charges	24,665	31,137
Alternative minimum tax and other tax credit carryforwards	10,296	10,296
Inventory, additional costs capitalized for tax	3,466	3,466
Unrealized loss on marketable securities	535	2,787
Other	1,593	1,522
Total deferred tax assets	286,180	292,383
Valuation allowance	(273,828)	(281,178)
Total deferred tax assets, net of valuation allowance	12,352	11,205
Deferred revenue	6,420	5,589
Property, equipment and other assets	1,013	706
Inventory, additional costs capitalized for financial statement purposes	537	542
Accrued liabilities	32	32
Other, net	4,350	4,336
Total deferred tax liabilities	12,352	11,205
Net deferred tax asset