CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2015		41,010
Balance at Dec. 31, 2015	$ 340,611	$ 410	$ 515,165	$ (174,964)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with acquisition (in shares)		4,075
Issuance of common stock in connection with acquisition	49,044	$ 41	49,003
Share-based compensation (in shares)		218
Stock-based compensation	6,625	$ 3	6,622
Equity component of 5.00% Convertible Senior Notes due 2021, net of tax of $8.6 million	13,526		13,526
Conversion of Bridge Notes (in shares)		273
Conversion of Bridge Notes	3,340	$ 2	3,338
Purchase of common stock for retirement (in shares)		(42)
Purchase of common stock for retirement	(598)	$ (1)	(597)
Total other comprehensive income (loss), net of tax	2,196				2,196
Net income (loss)	(45,835)			(45,835)
Balance (in shares) at Dec. 31, 2016		45,534
Balance at Dec. 31, 2016	368,909	$ 455	587,057	(220,799)	2,196
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation (in shares)		303
Stock-based compensation	7,204	$ 4	7,200
Purchase of common stock for retirement (in shares)		(61)
Purchase of common stock for retirement	(963)	$ (1)	(962)
Total other comprehensive income (loss), net of tax	(52)				(52)
Net income (loss)	72,621			72,621
Balance (in shares) at Dec. 31, 2017		45,776
Balance at Dec. 31, 2017	447,719	$ 458	593,295	(148,178)	2,144
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with acquisition (in shares)		1,108
Issuance of common stock in connection with acquisition	19,318	$ 11	19,307
Share-based compensation (in shares)		147
Stock-based compensation	6,196	$ 1	6,195
Purchase of common stock for retirement (in shares)		(47)
Purchase of common stock for retirement	(860)	$ 0	(860)
Total other comprehensive income (loss), net of tax	529				529
Net income (loss)	39,427			39,427
Balance (in shares) at Dec. 31, 2018		46,984
Balance at Dec. 31, 2018	$ 512,329	$ 470	$ 617,937	$ (108,751)	$ 2,673