Stockholders' Equity (Summary of Stock Option Activity and Weighted Average Exercise Prices) (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Options
Options outstanding, beginning balance (in shares) | shares	9,139.356
Options granted (in shares) | shares	140
Options exercised (in shares) | shares	(32)
Options cancelled or expired (in shares) | shares	(881)
Options outstanding, ending balance (in shares) | shares	8,366
Options vested and expected to vest (in shares) | shares	7,961
Options exercisable at June 30, 2016 (in shares) | shares	5,573
Weighted Average Exercise Price
Options outstanding, beginning balance (in dollars per share) | $ / shares	$ 11.05
Options granted (in dollars per share) | $ / shares	7.03
Options exercised (in dollars per share) | $ / shares	4.85
Options cancelled or expired (in dollars per share) | $ / shares	11.22
Options outstanding, ending balance (in dollars per share) | $ / shares	10.99
Options vested and expected to vest (in dollars per share) | $ / shares	11.00
Options exercisable at June 30, 2016 (in dollars per share) | $ / shares	$ 10.96
Weighted Average Remaining Contractual Term (in years)
Options outstanding at June 30, 2016	6 years 1 month 9 days
Options vested and expected to vest	6 years
Options exercisable at June 30, 2016	5 years 3 months 25 days
Aggregate Intrinsic Value
Options outstanding at June 30, 2016 | $	$ 1,738
Options vested and expected to vest | $	1,734
Options exercisable at June 30, 2016 | $	$ 1,731