Commitments and Contingencies (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Commitments and Contingencies
Rent expense	$ 1,300,000	$ 949,000	$ 2,500,000	$ 1,900,000
Non-cancelable commitments under operating leases
2016 (remainder of year)	2,546,000		2,546,000
2017	5,221,000		5,221,000
2018	5,960,000		5,960,000
2019	6,748,000		6,748,000
2020	7,077,000		7,077,000
2021 and thereafter	9,940,000		9,940,000
Total minimum payments	$ 37,492,000		$ 37,492,000