Subsequent Event (Details) (Subsequent event, USD $) In Millions, unless otherwise specified	0 Months Ended
	Feb. 24, 2014 item sqft
Subsequent event
Subsequent Events
Area of office building taken on lease	57,602
Initial term of the lease	10 years
Number of options available for lease extensions	2
Period for which lease tem can be extended	5 years
Annual fixed rent per square foot for the first year of the lease's base term	42
Threshold amount of annual fixed rent for the first year of the lease's base term	$ 2.4
Incremental annual fixed rent per square foot for remainder of the lease's base term	1.00
Amount of letters of credit issued as security	1
Area of office space not included in amendment	25,099
Amount of base rent payable extension period, if term of the existing lease is extended	$ 2.4