Income Taxes - Reconciliation of Statutory Federal Tax Rates and Effective Tax Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Statutory federal tax (benefit) rate	$ (2,736)	$ (4,526)	$ (8,781)
State taxes	(67)	609	(246)
Foreign dividends and unremitted earnings	1,745	1,493	(586)
Valuation allowance	1,596	2,456	7,367
Taxes on foreign income that differ from U.S. tax rate	(901)	(405)	2,488
Executive Compensation limitation	1,005	0	0
Non-deductible stock-based compensation expense	135	1,104	1,206
Expiration of attributes	1,478	893	330
Uncertain tax positions	120	435	362
Other	59	(317)	352
Total income tax provision	$ 2,434	$ 1,742	$ 2,492
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory federal tax (benefit) rate	35.00%	35.00%	35.00%
State taxes	0.90%	(4.70%)	1.00%
Foreign dividends and unremitted earnings	(22.30%)	(11.50%)	2.30%
Valuation allowance	(20.40%)	(19.00%)	(29.40%)
Taxes on foreign income that differ from U.S. tax rate	11.50%	3.10%	(9.90%)
Executive Compensation limitation	(12.90%)	(0.00%)	(0.00%)
Non-deductible stock-based compensation expense	(1.70%)	(8.50%)	(4.80%)
Expiration of attributes	(18.90%)	(6.90%)	(1.30%)
Uncertain tax positions	(1.50%)	(3.40%)	(1.40%)
Other	(0.80%)	2.40%	(1.40%)
Effective tax rate	(31.10%)	(13.50%)	(9.90%)