Segment and Geographic Information - Revenue by Product (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Product Type Reporting Information [Line Items]
Revenue	$ 21,884	$ 20,146	$ 20,429	$ 19,430	$ 18,364	$ 16,139	$ 18,268	$ 17,476	$ 81,889	$ 70,247	$ 64,402
Domestic [Member]
Product Type Reporting Information [Line Items]
Revenue									62,311	52,616	48,931
Domestic [Member] | Open-heart [Member]
Product Type Reporting Information [Line Items]
Revenue									37,843	32,880	29,202
Domestic [Member] | Minimally Invasive [Member]
Product Type Reporting Information [Line Items]
Revenue									13,648	12,733	14,166
Domestic [Member] | AtriClip [Member]
Product Type Reporting Information [Line Items]
Revenue									10,820	7,003	5,563
International [Member]
Product Type Reporting Information [Line Items]
Revenue									19,578	17,631	15,471
International [Member] | Open-heart [Member]
Product Type Reporting Information [Line Items]
Revenue									13,064	11,972	11,205
International [Member] | Minimally Invasive [Member]
Product Type Reporting Information [Line Items]
Revenue									5,354	4,813	3,824
International [Member] | AtriClip [Member]
Product Type Reporting Information [Line Items]
Revenue									$ 1,160	$ 846	$ 442