CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Operating activities
Net income (loss)	$ 8,058	$ 450	$ (4,712)	$ (9,700)	$ 8,508	$ (14,412)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Amortization expense	16,795		3,688		27,090	7,376	$ 14,752
Depreciation expense					394	355
Stock-based compensation expense					10,535	8,425
Non-cash lease expense					36	229
Non-cash interest expense for amortization of debt discount and issuance costs					3,860
Changes in operating assets and liabilities:
Accounts receivable					(8,242)	(3,333)
Inventory					(9,785)	(2,136)
Prepaid expenses and other assets					(2,005)	509
Accounts payable					1,935	(1,209)
Accrued expenses					(8,645)	(3,285)
Accrued rebates, returns and discounts					13,504	13,481
Operating lease assets and liabilities						734
Other long-term liabilities						(676)
Net cash provided by operating activities					37,185	6,058
Investing activities
Purchase of intangible asset					(368,226)
Purchases of property and equipment					(1,662)	(4,198)
Net cash used in investing activities					(369,888)	(4,198)
Financing activities
Proceeds from issuances of common stock from employee stock purchase plans					357	444
Proceeds from the exercise of stock options					6,080	299
Payments made for employee restricted stock tax withholdings					(1,922)	(523)
Proceeds from issuance of term note, net of issuance costs of $2,456					192,117
Proceeds from convertible senior notes, net of issuance costs of $5,473					138,277
Repayment of term notes					(12,500)
Repayment of term loan					(11,500)
Net cash provided by financing activities					310,909	220
Net (decrease) increase in cash, cash equivalents and restricted cash					(21,794)	2,080
Cash, cash equivalents and restricted cash at beginning of period		170,019		146,633	170,019	146,633	146,633
Cash, cash equivalents and restricted cash at end of period	148,225		148,713		148,225	148,713	170,019
Reconciliation of cash, cash equivalents and restricted cash to the Condensed Consolidated Balance Sheets:
Cash and cash equivalents								$ 145,678	$ 170,019	$ 148,713
Restricted cash								2,547
Total cash, cash equivalents and restricted cash	148,225	$ 170,019	$ 148,713	$ 146,633	148,225	148,713	$ 146,633	$ 148,225	$ 170,019	$ 148,713
Supplemental disclosure of cash flow information
Cash paid for interest					8,259	362
Supplemental disclosure of non-cash activities
Acquisition of property and equipment in accounts payable and accrued expenses					1,555	512
Accrued royalties discharged upon closing of asset acquisition					1,145
Inventory used in the construction and installation of property and equipment	$ 219				$ 613
Receivable from stock option exercises in other current assets						5
Operating lease assets assumed						9,957
Operating lease liabilities assumed						$ 10,691