Debt Obligations - (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Jul. 15, 2016	Jul. 25, 2011
Convertible Debt						$ 60,000	$ 60,000
Conversion of Stock, Shares Issued					540
Debt Instrument, Interest Rate, Stated Percentage							3.75%
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 17.00		$ 17.00
Contractual Interest Coupon	$ 0	$ 563	$ 0	$ 1,125
Amortization of Debt Discount (Premium)	0	899	0	1,793
Amortization of Financing Costs	0	123	0	246
Interest Expense, Debt	$ 0	$ 1,585	$ 0	3,164
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	386		386				4,634
Redemption of stock warrants			102		4,248
Stock Issued During Period, Value, Conversion of Convertible Securities					$ 10,525
Payments for Repurchase of Warrants			$ 1,025	$ 0	$ 9,500
Investment Warrants, Exercise Price			$ 23.13		$ 19.82
Common Stock [Member]
Redemption of stock warrants					80