Condensed Consolidated Statement of SHareholders Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Restricted stock units and Performance stock units	Restricted stock units and Performance stock units Common Stock [Member]	Restricted stock units and Performance stock units Additional Paid-in Capital [Member]	Convertible Senior Notes At 1.50%, Option Portion Convertible Debt
Shares, Outstanding		30,708,138
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 162,867	$ 9	$ 295,647	$ (443)	$ (132,346)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		122,376
Stock Issued During Period, Value, Stock Options Exercised	1,564		1,564
Restricted Stock, Shares Issued Net of Shares for Tax Withholdings							60,603
Adjustments to Additional Paid in Capital, Other	(1,271)							$ (1,271)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,544		5,544
Net loss	(11,735)				(11,735)
Change in unrealized gain on investments, net of tax	$ 425			425
Stock Issued During Period, Shares, Employee Stock Purchase Plans	61,691
Net loss	$ (16,592)
Change in unrealized gain on investments, net of tax	719
Shares, Outstanding		30,891,117
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	157,394	$ 9	301,484	(18)	(144,081)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		37,239
Stock Issued During Period, Value, Stock Options Exercised	527		527
Restricted Stock, Shares Issued Net of Shares for Tax Withholdings							434,838
Adjustments to Additional Paid in Capital, Other	$ (8,796)							(8,796)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	61,691
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 1,809
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	6,109		6,109
Net loss	(4,857)
Change in unrealized gain on investments, net of tax	294			294
Shares, Outstanding		31,424,885
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	152,480	$ 9	301,133	276	(148,938)
Shares, Outstanding		31,660,709
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	163,825	$ 9	313,963	179	(150,326)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		77,909
Stock Issued During Period, Value, Stock Options Exercised	731		731
Restricted Stock, Shares Issued Net of Shares for Tax Withholdings							64,161
Adjustments to Additional Paid in Capital, Other	(864)							(864)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,841		5,841
Net loss	(10,470)				(10,470)
Change in unrealized gain on investments, net of tax	$ (956)			(956)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period						705,835
Stock Issued During Period, Shares, Employee Stock Purchase Plans	126,046
Net loss	$ (13,938)
Change in unrealized gain on investments, net of tax	850
Shares, Outstanding		31,802,779
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	158,107	$ 9	319,671	(777)	(160,796)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		46,508
Stock Issued During Period, Value, Stock Options Exercised	594		594
Restricted Stock, Shares Issued Net of Shares for Tax Withholdings							372,639
Adjustments to Additional Paid in Capital, Other	$ (4,716)							$ (4,716)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	126,046
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 1,966
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	6,366		6,366
Net loss	(3,468)				(3,468)
Change in unrealized gain on investments, net of tax	1,806			1,806
Shares, Outstanding		32,347,972
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 160,655	$ 9	$ 323,881	$ 1,029	$ (164,264)
Carrying amount of equity component, net of capped calls									$ 23,307