Note 18 - Supplementary Financial Information (Unaudited) - Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	[1]	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	[2]	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer, Excluding Assessed Tax, Total	$ 102,896	$ 94,231	$ 86,285	$ 82,223	$ 86,531		$ 78,009	$ 69,814	$ 60,136		$ 365,635	$ 294,490	$ 348,201
Gross profit	61,599	54,482	49,109	47,631	49,526		43,462	39,611	32,546		212,821	165,145	196,503
Net loss	$ (13,408)	$ (16,180)	$ (20,578)	$ (22,745)	$ (21,631)		$ (22,665)	$ (28,464)	$ (22,991)		$ (72,911)	$ (95,751)	$ (74,904)
Basic earnings per share (in dollars per share)	$ (0.29)	$ (0.36)	$ (0.46)	$ (0.51)	$ (0.49)		$ (0.52)	$ (0.65)	$ (0.53)		$ (1.61)	$ (2.19)	$ (1.78)
Diluted earnings per share (in dollars per share)	$ (0.29)	$ (0.36)	$ (0.46)	$ (0.51)	$ (0.49)		$ (0.52)	$ (0.65)	$ (0.53)		$ (1.61)	$ (2.19)	$ (1.78)

[1] The Company recorded a charge of $7,000 due to impairment of a non-marketable equity investment.

[2] The benefit for income taxes included partial release of federal valuation allowance resulting from the transfer of an acquired in-process research and development to developed technology in 2018 which allowed the related deferred tax liability to be considered a source of income for realizing deferred tax assets, as well as the revaluation of the foreign deferred tax liability on the in-process research and development based on the foreign tax rates applicable to the anticipated reversal periods.