Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred revenue and costs
Deferred equipment revenue	$ 906	$ 6,499
Deferred fixed priced support or maintenance contract revenue	2,890	2,968
Other deferred revenue	3,262	2,355
Total deferred revenue	7,058	11,822
Less current portion included in other accrued liabilities	7,025	8,617
Long-term portion of deferred revenue included in other liabilities	33	3,205
Current portion of deferred costs included in prepaid expenses and other	258	2,961
Long-term portion of deferred costs included in other assets	1,267	4,325
Total deferred costs	$ 1,525	$ 7,286