Segment Information - Business Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Total revenue	$ 59,031	$ 105,549
Total gross profit	23,809	39,962
Supercomputing [Member]
Segment Reporting Information [Line Items]
Total revenue	30,243	84,728
Total gross profit	11,659	32,039
Storage and Data Management [Member]
Segment Reporting Information [Line Items]
Total revenue	15,545	13,467
Total gross profit	6,491	4,846
Maintenance and Support [Member]
Segment Reporting Information [Line Items]
Total revenue	29,737	26,803
Total gross profit	13,818	11,654
Other Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	13,243	7,354
Total gross profit	5,659	3,077
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	(29,737)	(26,803)
Total gross profit	$ (13,818)	$ (11,654)

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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