Segment Information - Summary of Revenue by Product Type (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Product Information [Line Items]
Revenue	$ 14,469	$ 10,555	$ 28,737	$ 18,862
Core [Member]
Product Information [Line Items]
Revenue	9,572	5,979	20,927	6,966
Wafer [Member]
Product Information [Line Items]
Revenue	2,857	3,312	3,952	9,369
Optical [Member]
Product Information [Line Items]
Revenue	1,765	1,154	3,403	2,298
Research & Development [Member]
Product Information [Line Items]
Revenue	272	110	397	208
Other [Member]
Product Information [Line Items]
Revenue	$ 3	$ 0	$ 58	$ 21