Segment Reporting and Geographic Information (External Revenue and Long-Lived Assets by Geographic Region) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 43,124	$ 38,175	$ 85,442	$ 77,080
Long-Lived Assets	5,248		5,248		5,555
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	3,199		3,199		3,326
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	13,555	13,676	26,411	25,801
Americas (Excluding the U.S.)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	126	855	682	2,480
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	26,522	21,869	53,101	45,290
Long-Lived Assets	2,017		2,017		2,194
Italy
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	21,400	17,300	41,800	35,400
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,921	1,775	5,248	3,509
Long-Lived Assets	$ 32		$ 32		$ 35