Income Taxes - Reconciliation (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
U.S. statutory income tax rate	35.00%	35.00%	35.00%
State tax, net of U.S. federal tax benefit	2.50%	2.90%	1.10%
Non-U.S. income taxes	(0.30%)	1.20%	0.00%
Nondeductible incentive stock option expense	0.20%	(0.40%)	0.40%
Research and development credit	(2.40%)	(0.70%)	0.00%
Change in deferred tax measurement rate	0.10%	0.20%	0.10%
Change in uncertain tax positions	1.50%	2.20%	(6.50%)
Expiration of capital loss carryforward	0.00%	26.90%	0.00%
Valuation allowance	(4.10%)	(267.60%)	(32.30%)
Other	0.10%	0.20%	0.00%
Effective income tax rate for continuing operations	32.60%	(200.10%)	(2.20%)
Valuation allowance	$ 6,156	$ 12,944