Commitments and Contingencies (Details)	1 Months Ended				3 Months Ended		6 Months Ended
	Apr. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Jan. 31, 2015 USD ($)	Nov. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) item	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Jan. 31, 2013 USD ($)
Operating Leases
Restricted cash securing letter of credit					$ 1,428,000		$ 1,428,000		$ 808,000
Future minimum lease payments
2015 (six months)					1,509,000		1,509,000
2016					2,441,000		2,441,000
2017					60,000		60,000
Total future minimum lease payment					4,010,000		4,010,000
Rent expense					500,000	$ 400,000	1,100,000	$ 700,000
Development and approval process costs		$ 13,500,000
Inventory Material
Future minimum lease payments
Purchase commitment					11,500,000		$ 11,500,000
Tests
Future minimum lease payments
Purchase commitment			$ 5,300,000
Contractual commitment period			18 months
Corporate Headquarters Lease
Operating Leases
Restricted cash securing letter of credit										$ 800,000
San Carlos Lease
Operating Leases
Restricted cash securing letter of credit	$ 300,000
Redwood City Lease
Operating Leases
Monthly base rent	62,700
Security deposit	$ 125,500
Patent infringement
Future minimum lease payments
Number of judgements appealed | item							3
Third-party payer
Future minimum lease payments
Amount sought				$ 1,880,000
Settlement amount					$ 1,180,000