Description of Business and Summary of Significant Accounting Policies (Computation of basic and diluted net income (loss) per share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of computation of basic and diluted net income (loss) per share
Net loss	$ (8,752)	[1]	$ (13,860)	[2]	$ (10,118)	[3]	$ (10,399)	[4]	$ (12,169)	[5]	$ (6,855)	[6]	$ 2,167	[7]	$ (6,848)	[8]	$ (43,129)	$ (23,705)	$ (22,333)
Weighted average common shares outstanding, basic and diluted																	35,480	31,870	30,716
Net loss per share:
Basic and diluted	$ (0.24)		$ (0.37)		$ (0.28)		$ (0.32)		$ (0.38)		$ (0.21)		$ 0.07		$ (0.22)		$ (1.22)	$ (0.74)	$ (0.73)

[1] Includes non-cash expense for stock-based compensation of $2.5 million.

[2] Includes restructuring and exit costs of $1.3 million, SEC and FCPA legal and settlement costs of $3.0 million and non-cash expense for stock-based compensation of $2.8 million.

[3] Includes acquisition related expense of $1.8 million and non-cash expense for stock-based compensation of $2.3 million.

[4] Includes restructuring and exit costs of $1.0 million and non-cash expense for stock-based compensation of $1.5 million.

[5] Includes impairment of assets of $1.2 million, non-cash deferred tax expense of $1.2 million in connection with the probable repatriation of a portion of the unremitted earnings of a foreign subsidiary and non-cash expense for stock-based compensation of $1.6 million.

[6] Includes non-cash expense for stock-based compensation of $1.1 million.

[7] Includes gain on sale of product line of $6.7 million, release of tax liability of $1.5 million and non-cash expense for stock-based compensation of $1.5 million.

[8] Includes non-cash expense for stock-based compensation of $1.2 million.